Which other family members count as dependants?
As well as spouse / durable partner and children, including grandchildren, under 21, you may also be treated as a dependant if you need your sponsor’s support to meet your essential living needs. You don’t have to show the reasons for the support your EU family member is giving you.
For parents and grandparents, dependency is assumed by the Immigration Rules so long as you apply before 30 June 2021.
You can submit your application from inside or outside the UK.