My mac has a partition that is free space is there a way to remove it?

You can try to see if it is a loose partition in disk utility. If it is a loose partition with no data on it, you can format it.

Make sure that you're not formatting your whole disk because that will erase the complete laptop. Make sure to have a backup of all your files before attempting anything in disk utility

It appears someone added an extra partition, then later deleted it. My guess it was a Windows Bootcamp partition and Bootcamp Assistant was not used to properly remove Windows & restore that partition into the main partition. Unfortunately Disk Utility is not a very good app and doesn't know how to reintegrate that unassigned space into the main partition.

You can use the command line "diskutil" to attempt to merge that section back into the main partition, but I'm not entirely sure of the exact options to use to do so. I do know a few years ago the correct command & options was posted here on this forum, but I don't recall the specific details. I just know the command options I suggested were not entirely correct, but the user was able to figure out the correct options to use for "diskutil" to make it work.

I don't have the time or a spare drive at the moment to experiment to provide you with the correct options for "diskutil".

Worst case, you perform a clean install of macOS by first erasing the drive (destroys all data on the drive) followed by reinstalling macOS & restoring from a backup.

Before you do anything, make sure to have a good backup first since attempting any partition modifications is always a risky endeavor which could cause you to lose access to the data on this drive. Hopefully you already have good backups since there are so many new ways to permanently lose access to the data on an internal SSD due to all the new hardware, software, and security changes.

I thought APFS formatting allowed expandable volumes.

I am thinking the free space is just indicating how much the volume disk0s2 can expand.