I guess prerequisites might include, you must know the person you want to contact you, and they must have a means of realistically contacting you. Contact meaning, messaging via technology in general sense.
Perhaps there are other prerequisites, but I’m interested in hearing about things people may have tried that worked, be they sigils, invocations, spells, or anything else. I haven’t seen much specific to this in my search.
I’m aware there are some youtube videos about such things, with many comments beneath saying it worked etc… (and some saying not), but my question is about what kinds of ways have you used that worked?