how to upgrade an Android device

[Android Central Question]

I wanna know how to upgrade my phone

 

[Rukbat]

Assuming that there is an update to your phone, go to Settings/About Device/Software update, and see if there's an update available. (If you do that more than once in 24 hours, all the rest of the tries, after the first one, will tell you that your phone is up to date. That's to keep the update servers from getting overloaded.)

Not all phones ever get updates, some get 1, some get 2, and the Pixel 2 and 2 XL will supposedly get 3.

(Other than Google phones, the manufacturer has to rewrite every update to match every model phone, and that's a lot of work, so for the cheap phones they usually don't, and for other than flagship phones they usually don't do more than 1. Then the carriers, if you have a carrier version [as opposed to an unbranded one], has to add their stuff - and, again, they may not want to bother if the phone isn't a fairly new flagship phone.)

If there's no update available for your phone, about the only thing you can do is obtain the source for the currrent version of Android from Google's site, modify it to work on your phone and compile it yourself. (Which is a lot of work and takes a lot of knowledge and at least a few years of software experience.)