When I try to install macOS big Sur and click on the hard drive I get an error volume not formatted for apfs

Is this computer running High Sierra as this is where the posting of you question is posted ??

Or this computer running Mojave as per user profile using a Mac Mini.

If Mojave exactly what version of Mojave ? Some time around Mojave 10.14.3 or 10.14.4 the Mojave update would Convert the Old HFS Journaled drive to the new APFS Format.

If this was not done - that might be the Source of the Error Message one has received.

If this is the case Follow this link to posting by @ leroydouglas for converting HFS Journaled to APFS format.

Sorry but do not follow the one word " safari " statement above.