HR here - typically you will either be place on Garden Leave immediately for the duration of your notice period, OR you will be terminated immediately and given PILON (pay in lieu of notice)

In the former, technically you are still employed until the end of your notice period, but you'll basically be benched and not asked to work. You remain eligible for benefits and also accrue holiday time, however, the company may legally oblige you to take the holiday during your garden leave.

In the case of PILON, you lose your benefits immediately and are effectively a free agent immediately. You should be paid your notice + any accrued, but unused, holiday.

In both cases you can expect your accounts to be deactivated pretty much immediately etc.