Why? What do you expect the update to do for you? That is a semi-serious question: people often overestimate the difference that updates actually make.
More seriously, what software version are you on? It may be that no update exists for your phone. Like any mobile OS, Android updates must be built for the particular model, so there will only be an update for this phone if LG have made one (or, if it's a carrier-branded model, if the carrier have made one based on LG's update). Although there are circumstances in which it won't work, in general going to "Software Updates" in your settings and pressing "check for update" will tell you whether there is one or not. Since this is a budget phone from 2016 I think the chances of there being any further updates for it are slim, but if we don't know what software version you have we've no way of telling whether you have missed one.
If there are no official updates there may be unofficial ones, if anyone has bothered to make them. I'd see whether there is a section for this phone at xda-developers and look there. Root and a custom recovery will be required to install them if there are (which means unlocking the bootloader first - one-click root tools, always a bit dodgy, don't work with Android 6 or later). If this stuff does exist for that phone, do your research before deciding whether to do it, and back up before you do anything else. And do not attempt to install either a ROM or a recovery that was built for a different phone model - your phone will cease to work if you do.
There is no generic Android version that can be installed on any device, so those options (official update from LG or custom ROM if somebody has made one) are the only possibilities. Apologies if you knew that, but since we don't know anything about you I thought it best to be clear.