If you use Minecraft Fabric generator, you need to have that installed too. MCreator mods need to have Minecraft Forge installed in order to work. You will need Minecraft Forge in either case. MCreator mods can be installed on both the Minecraft client and server. Select a destination and the mod will be exported to a file. MCreator will build all resources and sources.

To export your mods, open MCreator and click on the export button which is located in the top toolbar. Enter the mod details and click Export.