How do i add my own Plugins

Okay i have a lot of plugins and i would like to use them but how do i upload them to my server

like i have a lot of plugins that i cant find in the plugin list and i would like to use them and i have payed plugins also like MCMMO for just one payed plugin you can find that plugin but it will not work with 1.13.1

now that is messed up

so i have to request plugins from spigot that i payed for

and i dont think that is right