Good practice to remove after merge? If deleted, how do I track a merge history?

Question

My friend and I are working on a personal project, creating branches when we go, and merging them back into masters when the function is executed. But merging, and then deleting the branch, makes it a straight line in the log (see Figure), which seems bad for tracking history. What should we do to work as a team and keep track of the history, as shown, before the branch is deleted?

Answer 1

master, git fast-forward-merge. , , . , .

git merge --no-ff, .

?.