Can I use a 15 amp outlet on a 20 amp circuit. Wire with 12 gauge wire.

Yes.

15amp outlets are made for 14 gauge wire. The 12 gauge wire of a 20amp circuit may not fit into a 15 amp circuit. Properly or take more time to install. Cost of a proper 20 amp outlet is low. Be sure to pigtail outlets: do not wire through the outlet by connecting the outlet in between the two cables of a run because all the current in the circuit then runs through the outlet. A 15amp outled wired incorrectly in this regard would be even more susceptible to overheating, burning up, causing a fire.

15 Amp receptacles are allowed by Code, and are designed to connect to 20 Amp circuits with #12 wire.

While pigtailing is better method, receptacles are designed and listed for feed through.

Regarding feedthrough connections: I have had to repair several house circuits which were wired feedthrough, replacing all the burned outlets on circuit. Cutting back burned & arcing #14 wire. (Never with #12) Also replacing burned up 15 amp breakers. The homeowners were using trial & tripout to load the 15amp circuit to just below it overloaded, for prolonged times. This is not a rare event in my experience, particularly with heavy electronics plus heaters, water cooler, & small refrig or freezer. (despite my severe tongue lashing of homeowners) In addition, the outlets had the wires pushed into the back rather than more securely connected with screws, which I believe contributed to the problem. Common fast lazy installation method. I disagree about using #12 wire with cheap (or older) 15amp outlets. Cheap outlets are hard to wire with #12, & holes in back are too small to push #12 into. You are using quality materials & wiring correctly so no problems like this!

15amp outlets are made for 14 gauge wire. The 12 gauge wire of a 20amp circuit may not fit into a 15 amp circuit. properly or take more time to install. Cost of a proper 20 amp outlet is low. Be sure to pigtail outlets: do not wire through the outlet by connecting the outlet in between the two cables of a run because all the current in the circuit then runs through the outlet. A 15amp outled wired incorrectly in this regard would be even more susceptible to overheating, buring up, causing a fire.This is completely incorrect.

Unless you are in Canada, using 15A recweptacles on a 20A circuit is ABSOLUTELY FINE.

I am not sure where you are getting your information from ElecPro81, but 15A receptacles ARE rated for 20A feed-thru.

Also, #12 is no harder to work with as far as receptacles go. There is NO DIFFERENCE when using the side screws as most real electricians do. Yes, receptacle "back-stab", or quick-wire, connections are no longer rated for #12. This is an age old problematic issue which is why almost no one uses those connections on devices.