How to Inspect Element using Safari Browser

In your Safari menu bar click Safari > Preferences & then select the Advanced tab.

Select: "Show Develop menu in menu bar"

Now you can click Develop in your menu bar and choose Show Web Inspector

You can also right-click and press "Inspect element".

EDIT As suggested by @dennis in the comments: If you dont see "Show Develop menu in menu bar" you may need to run DevToolsSecurity -enable in the console before the option is visible

Press CMD + , than click in show develop menu in menu bar. After that click Option + CMD + i to open and close the inspector