One setting controls how every date in Grape is written: in note lists, note info, version history and template variables.
Picking a format
Open Settings and go to the General tab. Date Format offers common presets, each shown with today's date as a live preview, and Time Format switches between the 12 hour and 24 hour clock.
A custom format
Choose Custom and a field appears for your own pattern, like dd.MM.yyyy or EEEE, d MMMM yyyy. Letters stand for parts of the date, punctuation comes through as typed, and words go in single quotes. The field previews the result as you type.
Where it matters most
Template variables render with these settings, so a daily note template produces titles in exactly the format you chose. The Templates settings tab shows worked examples using your current format.
Per device or everywhere
Like most preferences, the format syncs across devices with your settings, so pick once.