Although Minecraft's Java and Bedrock Editions are quite different, it's still possible to convert an existing Java world to Bedrock if you don't mind there being some differences to the world ...

Minecraft players can customize their games using a plethora of add-ons or mods, depending on which version they’re playing. Players on Bedrock Edition will primarily use add-ons, which can be ...

You need to have the game's Java Edition to add the mods. Bedrock Edition does not support mods and can only get add-ons that offer limited features and functionality.