a crack in the glass

Dear Rob,

Now it depends on which one you have but it's very possible

Apple iPhone

Choose the one you have.

Buy the kit

You want to follow the Replace Front Panel Guide.

Use the right tools, follow the guide, take your time and look forward to that great feeling of fixing it yourself.

It's useful to read what other problems people have had. Especially trying to take off a broken screen.

Good luck