Regular Minecraft doesn’t know what mods are, so it will completely ignore your mods folder and never do anything with any files you put in there unless you “teach” it to look there, and what to do with the files it finds.
The usual “teaching” method is by installing Forge, which is exactly designed to teach Minecraft to look for and load stuff you put in the mods folder (among other things relevant only to mod-makers).
- Download it. Choose the “Recommended” build for your version of Minecraft, and click the “installer” link.
- Run the installer.
- In the Minecraft launcher, choose the new profile named “Forge” or similar and click Play.
If you want greater explanation of how the installation process works, you can read the Installation article on the Forge Wiki.