I created free space and I don't know to recover it So I followed this answer here
Merge partitions with Macintosh HD

And I ended formatting my old bootcamp partition into free space.
But now I am unable to see the free space anywhere. When I go to disk utility it just says that I am using 200 GB of storage even though I have 256 GB with 50 GB just gone, somewhere.

Diskutil cs list
Shows nothing
Basically you need to enter the following commands in a Terminal application window. The first command removes the OSXRESERVED partition. This partition is for the Windows installation files. The second command expands the disk1 container to consumer the missing free space.

sudo  diskutil  erasevolume  free  none  disk0s3
sudo  diskutil  apfs  resizecontainer  disk0s2  0