I’d write a bookmarklet for that case:
javascript:
{
const name = 'ABC';
const d = new Date();
const year = d.getFullYear();
const month = d.getMonth();
const date = d.getDate();
document.activeElement.value = `${year}/${month}/${date} ${name}`;
void 0;
}
This bookmarklet inserts the desired text into the currently focused text box. Tested on Lemmy Web UI.



Although committing the feature to the Github repository has finished, the feature will be available for you when your instance updates the Lemmy version to 0.20, 1.0, or higher.