I would like to use my personal domain to reach HA from the outside but I have not found any guides about it. Can someone help me?
Thanks 
I forgot to mention that i have a static ip.
Place your ssl certificates somewhere that home assistant can see them, then read this HTTP - Home Assistant
You will also need to forward port 8123 from the outside your LAN to the computer you have home assistant on.
I assume you have a dns record pointing your domain to your static IP.
Yes, my ip address already points to my domain and the ports are already open. I guess I just miss the certificate that I don’t have. Should I then install Let’s Encrypt on HA?
Thanks for the reply
That does seem to be the most popular option around here
There is an addon if you are on the HA operating system or a supervised install.
Yes, I just installed Let’s Encrypt. Can you help me compile the configuration file?
I don’t know how to fill in the challenge and dns fields
Neither do I. There are some instructions in the documentation tab in the addon.
Found! Thanks