Hi patrickm

In order to apply you must show that:-

- You are seeking leave to enter the United Kingdom as the spouse (or civil partner) of a person currently living and settled in the United Kingdom or returning to the UK with you to live there permanently.
- You are legally married to each other or have registered a civil partnership;
- You are both at least 21 years old on the date when you would arrive in the UK or when we would give you permission to remain.
- You intend to live together permanently as husband and wife, or as civil partners.
- You have met each other.
- You meet our English language requirement.
- You can support yourselves and any dependants without help from public funds
- You have adequate accommodation where you and your dependants can live exclusively and without needing public funds.


What documents are required?
You must send:-

- 2 recent passport photographs and your passport - see the Photographs and passport page
The applicant must present a valid passport with at least 6 months validity remaining.

- Evidence of your age and your partner's age.
There are no immigration rules about specific guidance on age difference between the applicant and sponsor.However, the applicant must be aged 21 or over on the date of arrival in the UK and the applicant's spouse must be aged under 21 on the date of arrival in the UK.

- Your marriage or civil partnership certificate

- Evidence that you were both free to marry or enter your civil partnership, if either of you was previously married or in a civil partnership
Evidence would include Death Certificate of the deceased spouse/civil partner, evidence of divorce (eg divorce Decree Absolute), Annulment or Dissolution Certificate.

- Evidence that you have met
Photo's of you both together as a couple, photo's of the wedding, e-mails, Chat logs and Text messages showing that you had met and married.

- Evidence of your English language ability - see the English language page

- Evidence that you can maintain yourselves and any dependants adequately without needing public fundsmaintenance (funds) page
You and/or your partner must demonstrate that you and/or they can cover your living expenses in the UK for 27 months, if you are applying from outside the UK. You will not have access to most public funds (such as state benefits) during your probationary period.

The Evidence of maintenance page describes the documents that you should submit to prove that you meet this requirement.
Please take a look at the Evidence of maintenance (funds) page which clearly indicates the type of documents needed.

Your bank statements will normally show your income and your outgoing expenditure. ECO's are not accountants but, if you are generally living within your means and can afford the cost of another adult consumer joining the household, this should be immediately obvious.

Only those people with a discretionary amount of money close or equal to the equivalent of means-tested benefit might feel the need to make a budget plan to signpost how they can afford another consuming person in the house.

- Financial Standing
The application must be supported by evidence that proves the applicant will not require public funds. Generally this takes the form of the sponsor/applicant (or co-sponsor) providing:-
Bank Statements covering at least 3 months (preferably 6 months)
Salary slips for at least the previous 3 months.(preferably 6 months)
The sponsor's employment contract (if the sponsor is not independently wealthy). A letter from the employer will be OK

- Evidence of your accommodation

Accommodation - General Requirements
The Rules require that there must be adequate accommodation for a spouse or civil partner and any dependants.
The ECO will be looking for evidence that the accommodation complies with the following requirements:-

- It is (or will be) owned or legally occupied for the exclusive use of the couple.
- It is capable of accommodating the couple, and any children, without overcrowding as defined in the Housing Act 1985.
- The ECO should be satisfied that housing the couple in rented accommodation will not be in breach of any tenancy agreement as regards sub-letting.
- That no additional public funds will be necessary for accommodating the applicant in cases where the sponsor lives in accommodation from public funds.

Accommodation shared with family/friends
If the sponsor and the applicant are to live in accommodation with other occupants such as family/friends/etc), then provide:-

- Co-sponsor(s) owns home
Include a certified copy of the deed showing this, or other proof of ownership.
If the co-sponsor has a mortgage, the appropriate entry from the Land Registry can be provided,(available online for a small fee), or a letter
from the lender.The mortgage payments should appear in the bank statements of the co-sponsor.

- Co-sponsor(s) renting apartment or house
Include a copy of the tenancy agreement.
If the applicant is not a signatory to the tenancy agreement, then an additional statement from the landlord (or estate agent) should be provided
confirming both the size of the property and agreement that an additional occupant may take up residence there.
If an existing tenancy agreement is to be used, it should have at least six months before expiry. If the tenancy agreement does not have at least
six months before expiry, then an additional statement from the landlord/agent showing intent to renew at the same terms should be provided.

If the accommodation is owned by a local authority or council estate, a landlord's confirmation should also be obtained, but if this cannot be
obtained a report from an independent surveyor which confirms the size and suitability of the premises can be submitted instead.

Hope this will help to get you started.
Plenty of threads to give more detail, just make a search.

Most important of all is to research the UKBA website fully. Please do follow as many of the provided links as possible.

Good luck