Newer home owner here. I have these cracks on the foundation of the house. Behind them is a crawl space open to dirt. How should I fix or address these? Do they need to be fixed? I try and DIY as much as I can so don't be afraid to suggest a DIY solution. I'm also not above getting professional help, I just haven't had to thus far.
When you bought the home, what did your home inspector say about the foundation cracks?
Call a professional to do a foundation inspection. Your cracks might be nothing or they could be serious. Only a foundation expert can tell you for sure.
No stranger on the internet will have better advice than the honest local expert.
The only advice I can give for household things is that if you want your investment to actually mature properly, you have to listen to the professionals. They'll save you lots of money in the long run.