Arduino Uno + Sim808: Using HTTP client for GPRS GSM
Start Arduino IDE, open the Library manager, search for SIM800 and there is 3 libraries available there that you can install. The advantage is that this libraries is kept up to date and when a new version is available you will get a notice to upgrade.

There is a HTTP PUT/GET library "HttpClient" that can be installed the same way as above.

Or

If you googlem using "sim800 library arduino" you will find several libraries like:

https://cristiansteib.github.io/Sim800l

or on github:

https://github.com/search?l=Arduino&amp;q=sim800&amp;type=Repositories&amp;utf8=%E2%9C%93

And as I understand it the 808 is GSM/GPRS + GPS, so the GPS features isn't normally covered by these libraries.