Here we have listed the hotkeys available in Overleaf. For Mac users, the below commands will use the cmd key instead of Ctrl.

Command Operation
Ctrl + f Find and replace.
Ctrl + Enter Compile the project.
Ctrl + z Undo.
Ctrl + y Redo.
Ctrl + Home Go to first line of the current file.
Ctrl + End Go to last line of the current file.
Ctrl + l Go to specific line (opens a dialog)
Ctrl + / Toggle commenting for selected lines. (Comment/uncomment selected text.)
Ctrl + d Delete current line.
Ctrl + a Select all.
Tab Indent section.
Shift + Tab Un-indent section.
Ctrl + u Change selected text to upper case.
Ctrl + Shift + u Change selected text to lower case.
Ctrl + b Bold.
Ctrl + i Italics.
Ctrl + Space Open autocomplete menu, inside of \cite{...} search the bibliography.

A more comprehensive list of keyboard shortcuts can be found in this Overleaf project template.