Up to 3,276 fans will be allowed to watch the Premier 15s final on Sunday, 30 May at Gloucester's Kingsholm.
Saracens host Loughborough Lightning and Harlequins are at home to Wasps in the semi-finals on 22 May.
Nicky Ponsford, the Rugby Football Union's (RFU) head of women's performance, said the return of fans was "brilliant" for the English women's top flight after a "difficult season".
The semi-finals and final will be broadcast across BT Sport.
Saracens and Harlequins have semi-final home advantage after finishing as the top two sides at the end of the regular season, and fans will also be able to attend those fixtures.
It will be the second time a men's Premiership ground has hosted the final, which was played at Northampton's Franklin's Gardens in 2019.
The teams have been playing under adapted laws to minimise contact during the pandemic after the 2019-20 season had to be cancelled.
Kingsholm had been selected to host the 2020 final and Gloucester's chief executive Lance Bradley expressed his delight at welcoming back fans for the 2021 showpiece instead.
"We know that supporters are eager to return to live sport, and this final is the perfect opportunity to join us at Kingsholm and celebrate live top-flight rugby returning to our stadium," Bradley said.
Saracens have won both the previous two titles, beating Harlequins in the final both times.