How to join to two different mesh models into one?

Support Modeling
1

I have the base model entirely made from one box mesh. To complete my model i had to add a cylinder mesh and join them together.

They are in contact with each other but in scene collection they are separately listed as cube and cylinder.

How do i fully join them together as one?

2

Select both then press CTRL+J.

Dj

3

Thanks a lot!