How can you combine meshes?

I have 2 meshes that need to be combined and they also have 2 textureID. Is there any way I can make them 1 mesh and textureID.

Is this in Roblox, or your modeling software? Assuming you’re saying TextureID meaning it is Roblox, the best solution I could give would be to group it as a model, but I don’t believe there’s anything else you can do beyond that since I believe only Parts can be unionized, not MeshParts. If you are able to enter your modeling software, there’s a high chance you can join the two parts together there, then use Blender to reset and smart unwrap your UVs to get a proper model that you can texture. I hope this helps!