You just buy hosting at almost any hosting provider, this cost about $10/month.
There are some requirements though, the most important is php support:
https://www.photo.gallery/v2docs/requirements
Rule of the thumb - dont get anything that says "windows". Generally speaking almost any modern hosting should be fine.
Here are some recommendations from our users:
viewtopic.php?t=2714
I would recommend you to get hosting space in the part of the world you live. Ie. if you in USA, get it from US company, same for Europe. This is related to trans-atlantic cable, it will just work faster for you this way.