After Steve Carrell left The Office and departed as Michael Scott, taking with him Amy Ryan's Holly too, we didn't really ever hear much about the two characters and what they got up to in life post-Dunder Mifflin. We know they settled down and started a family, but as for the specifics there, nothing ever made it onto television.
However, in Jenna Fischer and Angela Martin's The Office Ladies podcast (thanks, Variety), where they provide an inside look at the popular series, it was mentioned that Michael and Holly's kids were in fact named, and frankly you will never guess what their names are.
According to the pair, the kids ended up being named Chebonshur and Lowshebin, and as for how those names came about, Ryan also mentioned in a special cameo that Michael named the kids "based on the feeling he had when he first saw them." This explains a lot.
Since The Office is all wrapped up now with no plans to continue with this batch of characters, it's highly unlikely that we'll see Chebonshur and Lowshebin ever appear on-screen.