meaning of "flag this message"

what is the meaning of " falg this message" ?

Hi,

I assume you mean flag this message. ‘Flag’ or ‘flag up’ in this sense means ‘make a note of’ - ‘remember this for the future’.

Alan

It can also mean to mark the message in some way (with a red pen marking, with a sticky note, etc.), so that you or other people will notice it and not forget it.

thanks a lot for your help