You will have to switch to 1.12 to play mods as forge hasn't updated.

Use Fabric loader it's really easy and there is a lot of documentation for it.

Here's a video to help you out 😉

youtu.be/2fP3T1DwvsI

If my reply helped you please like and sub me on pmc

Depends on the version. 1.14.4 mods are scarce as it is a new version. Personally I use forge to play with my mods.
As star_weaver said, get the stopmodreposts addon. Use curseforge to download you mods.
If you want to do the twitch way, do what they said.
But if you want to use forge, go to this link: http://files.minecraftforge.net/
Download the version of forge you wish to play on.
Run the file from forge so you can download the client.
Go to your search bar and put in %appdata%.
Go to .minecraft, then to the 'mods' folder. From there you paste the .zip or .jar files into it.

first up, get this browser addon to help keep yourself safe: https://stopmodreposts.org/
then get the twitch launcher from here: https://www.twitch.tv/downloads
or multiMC from here: https://multimc.org/
and using the launcher of your choice make a new minecraft instance and install forge, then download the mods you want from websites that dont say its a repost site through that addon, curse, curseforge, pmc are a few safe sites and make sure the version of minecraft matches the version of minecraft the mod was made for. EG a mod made for 1.7.10 will not work on anything other than 1.7.10, same with 1.12.2 and so on