It seems to vary a lot?
When I tried to renew my sub a wee month ago,
due to danish banks are being fidgety, one has to approve your buy with using a silly app for approval.
Buying through Swtor-website was a big no-go. They have seemingly not implemented this functon properly.
I had to reinstall the game through Steam, and buy the sub through Steam.
Thankfully, that worked without a hitch, and my PTSD didn’t bloom up again.