Option number one
git reset --soft HEAD~3 // number of commits back grom the head
git add -A
git commit --no-verify -m "squashed"
git push --force // or iw work in one branch with teammates git push --force-with-lease
Option number two
In jetBrains products
Git -> popup on selected commits -> squash
Option number three
In Tortoise Git
Show Log -> Selected commits -> Squash // but here should be clean working tree