I started to use SourchTree recently.
The default format of the diff is to use "-" or "+" to show changes.
I like to have 2 files side-by-side and show the change line to line.
However, I cannot find the option to change the format. Can you help?
If you don't see any "side-by-side diff" button on the diff view, then a good workaround is to setup a difftool in your SourceTree.
See for instance "How to use Meld as a merge tool with SourceTree on Windows?".
Using an external diff tool (supporting natively a side-by-side view) is more reliable than the native tool options here.