Hi @johndetman
It means that there is a charging problem or a problem with the battery charge being too low.
Did you mean a Moto G6 mobile phone?
Mobile phone batteries are removable as long as you have the appropriate tools, instructions and the correct replacement battery to do so.
Here's the ifixit [guide|127829] guide that shows what to do and the tools necessary to do it with.
Unfortunately, ifixit doesn't currently have any replacement batteries for the model, in stock, so search online for [https://www.google.com/search?client=firefox-b-d&q=hg30+battery|HG30 battery], to find suppliers that suit you best.