There are mainly two ways to waterproof electronics circuits:
1.Resin potting;
2.Surface coating- Waterproof adhensive.
BTW, Resin potting often adopts epoxy resin potting glue, which is used for potting of electronic product modules so that it is able to wrap the whole PCB and protect it from water, moisture, salt spray, mold, earthquake and resistance, External force shocks, etc.