What is a Git branch?
Branches in Git are independent lines of development within a repository. Each branch represents a snapshot of the project's files at a certain point in time. When you create a new branch, it initially contains the same commits as the branch you created it from.

Separate branches can be merged into one branch. The diagram below illustrates how development can take place in parallel using branches.

Changes in the primary or other branches will not affect your branch unless you pull the latest changes from those branches.
It is a common practice to create a new branch for each task (i.e., bug fixes, new features, etc.). This method lets others easily identify what changes to expect and simplifies backtracking.