If you are the husband, wife or civil partner of an individual who has settled status in the UK, this is the visa category you will be required to
apply under should you wish to join them in the UK. In addition to spouse
relationship, the immigration rules do acknowledge the significance of
unmarried partner relationships. They are given same rights as enjoyed by the spouses where “Two persons living together in a relationship akin to
marriage for at least two years would be considered as unmarried partners of each other”.

If you are the parent of a child living in the UK , and you either have sole
responsibility for the child , or a genuine subsisting parental relationship
with the child then you can apply for a visa proving you can meet show you can maintain and accommodate yourself adequately in the UK. You must also have the intention to take an active role in the upbringing of the child.  There is no definitive financial requirements for this visa, but it can be a complicated application to get a right and legal assistance is recommended.

If your application is successful under this category, you will be granted
permission to live and work in the UK for a period of 30 months. At the end of this period you need to apply for a further period of stay in order to bring your total stay in the UK to 5 years.  Providing you are still married or in a civil partnership and you plan to live with your spouse/civil partner permanently in the UK, you may apply to settle permanently, currently known as Indefinite Leave to Remain.

It is important to note that if the settled spouse has more than one wife or
husband overseas, only one will be allowed to join them in the UK.

Requirements of the settled person in the UK

If you wish to join your husband, wife or civil partner in the UK you must
first ensure that:

They are at least 18 years of age.
They currently reside and have settled status in the UK; OR
They are coming to live permanently in the UK.

Requirements of the applicant intending to join their spouse/civil partner in
the UK

The requirements for the applicant intending to join their spouse/civil
partner in the UK may at first glance appear to be simple; however in reality
when preparing the application the opposite is often the case. Applicants are
advised to pay careful attention to the requirements and to seek clarification
on any matter of uncertainty:

You, the applicant should qualify to apply for a spouse/civil partner visa
if you are able to demonstrate the following:

You are both at least 18 years of age.
You have met your spouse or civil partner previously.
You are legally married to your spouse or you are in a civil partnership
recognised in the UK.
Your spouse or civil partner is present and settled in the UK, or returning
with you to reside in the UK.
You and your spouse/civil partner both intend to live together permanently.
You are able to meet the minimum income requirements

You are able to meet the English language requirement
You have adequate accommodation for yourself and any dependants which is owned/rented by yourselves without assistance from UK public funds.

In order to be able to demonstrate that you satisfy the above requirements, you will need to provide supporting documentation.

Please note that It is possible for application to be refused due to the
lack of supporting evidence which in many cases is simply just overlooked by the applicant. Although the refusal of a spouse/civil partner visa triggers a right of appeal, unfortunately the process may just take too long to be
considered by the Entry Clearance Manager or the Asylum and Immigration
Tribunal (AIT) and therefore it is crucial that the application is prepared
well from the outset.

It is advised to pay careful attention to even the most minor details before
submitting your application under the spouse/civil partner category. We
recommend all applicants to obtain legal assistance in the event that they
require clarification or assistance with applications and we have a wealth of experience with handling these applications.