The family contribution limit may be split any way you choose but the catch-up provision is individual only. Also note that each HSA account is owned by one person only, there are no joint or marital accounts.
So assuming that both spouses are covered by a family HSA and have no other disqualifying coverage, then the overall limit for 2021 is $9,200. The first $7,200 can be split any way you like but the $1000 catch up is individual. So each spouse could contribute $4600, or spouse A could contribute $8200 and spouse B contributes $1000, but neither spouse could contribute $9200 to a single account.
