Modify /etc/fstab
Add discard options in /etc/fstab as below
UUID=2741f09c-7667-4b4a-88da-f2db826c12345 / ext4 defaults,discard,noatime,nodiratime,commit=600,errors=remount-ro 0 1
Use command to trim SSD
# fstrim -a -v
/: 811.9 GiB (871748583424 bytes) trimmed
Ref : Debian SSDOptimization