Ford changed F-150 coolant with the 2019 model year. Ford's owner's manuals for 2014-2018 trucks specify Motorcraft Orange Prediluted Antifreeze/Coolant VC-3DIL-B (Ford spec WSS-M97B44-D2), first changed at 6 years or 100,000 miles and then every 3 years or 50,000 miles. From 2019 they specify Motorcraft Yellow VC-13DL-G (WSS-M97B57-A2), first changed at 10 years or 200,000 miles and then every 5 years or 100,000 miles. Both are pre-diluted - do not add water, and do not mix the two. The full cooling system holds roughly 3-4 gallons depending on engine and cab (twin-turbo EcoBoost engines hold more than the 3.3L V6); a drain-and-fill uses about 2 gallons of premix, a full flush uses 2-3 gallons plus 3-4 gallons of distilled water for the rinse.
A DIY flush costs about $25-$45 in fluid, versus $80-$130 at an independent shop or $130-$180 at a Ford dealership, and takes 45-60 minutes. The basic procedure: let the engine cool completely (2+ hours, since a hot pressurized cap can spray 200F+ coolant), drain the old coolant from the radiator petcock, close it and run distilled water through the system to rinse, drain again until it runs clear, refill with the Motorcraft premix your model year calls for (do not dilute), then burp the system by squeezing the upper radiator hose to release trapped air and check for leaks.