Converting Sram Force 22 crank to Force 1

First of all, you absolutely don't need to replace Force 22. The crank arms have removable direct mount spider that the chainrings are bolted to. That means, in theory, you can put almost any chainrings given a matching spider exists - a very versatile system that's gained popularity over the recent years (Red/Force AXS are direct mount only, unlike Red 22).

If I just swop the rings for the a narrow wide Sram Force 1 chainring will this automatically fit into my existing crank arm?

Also if I do just replace the rings, would I need smaller chainring bolts or will the existing ones work

If I were to convert Force 22 to 1x, I'd check the following:

1. For regular chainring (mounted to spider), BCD (bolt circle diameter) should match. Force 22 came in 110mm and 130mm varieties. BCD limits minimal chainring size - the bigger the BCD, the bigger smallest compatible chainring is.
2. For regular chainring, chainring bolts should be compatible. Bolts are two-piece (nut and bolt), some are single piece (bolt screws into chainring). You can visually inspect existing bolts to check what you have, I don't have hands-on experience with Force 22 in particular. With a single chainring, the bolts might be too long and require spacers.
3. For regular and direct mount chainrings, you might want to factor in chain line (determines relative positions of cassette and chainring centers). For 1x road/gravel applications, it should be relatively safe to put the chainring on outer ring position, at least in my experience (I run 1x setup on my road bike with 2x crank arms). Spider design (I suspect Force 1x spider might have different offset/chainline to that of Force 22, but I can't say for sure), spindle length/interface and rear hub width (130mm non-disc road, 135mm QR/142MM TA, boost and so on) affect the chain line too. Force 22 can have GXP and BB30 spindles (there are true BB30/short and long BB30/BB386 varieties, at least for S2200). I only have experience with SRAM S2200 arms (very similar to Force 22, if not the same), when I was in market for a 1x chainring, this was an important factor. Direct mount chainring manufacturers usually specify what spindle/hub width the chainring is for. The spindle type is written on the spindle, the length can be measured with a ruler.
4. For direct mount chainring, take a note of chainring interface. There are a lot of varieties, but Force 22 has the 3-bolt Truvativ/SRAM pattern. Newer SRAM offerings have different interfaces.

Personally, I'd swap the whole spider assembly to a direct mount chainring because it looks cleaner. See manufacturers like Absolute Black, Garbaruk, Wolf Tooth and many others.