3.7 V, 80 mA = 0.08 A, H means 1 hour, or 3600 seconds.
To summarize, this lithium battery can provide 3.7*0.08*3600J (Joules) of energy. Of course, this energy is electrical energy.
For this battery, it produces current at a voltage of 3.7 V, the current intensity is 80 mA and it can produce for 1 hour. Of course, this voltage of 3.7 V is the voltage that allows your device to operate normally.
If the total energy of the battery remains unchanged and the voltage requirement is high, then the other two elements can obtain lower values. The same goes for everything else, and vice versa of course. If the current intensity required by the device is not 80 mA, but only 10 mA, and the required voltage is 3.7 V, then an increase of 80/10 times can be achieved in the time.