Saving .ai fonts as curves/outlines?

I sent somebody a few .ai files and they said that it was saved incorrectly and I have to save the font as curves/outlines. What does this mean? Is there just a way to save it like this or do I have to go over it with the pen tool?

I assume we are talking about Illustrator here.

Just select everything (ctrl+A) and press ctrl+shift+O - all the fonts will be convered to outlines.

Doing so “translates” the texts into vector objects, so the person opening your file and NOT having these fonts installed, will be able to use this file.
Without fonts converted to outlines/curves, they’d be replaced with default fonts and your design would look different.

That’s why converting fonts to outlines/curves is always recommended when you are giving your final files (for print for example).

Ok another question. These are going to be used for making vinyl stickers. The thing is that 2 of the letters overlap eachother and are supposed to. But when i transfer them to paths if the guy puts it into the computer to cut they’ll cut where the paths are. So, I need to connect the paths from 2 different layers.

How do I get this to work?

Sorry if these are really basic questions, I usually just use photoshop for vectors…

EDIT: The error messege says:

Use the “Merge” operation from “Pathfinder” tab to make 1 object from overlapping shapes.