Content in footer can be added via block regions.
There are 8 block regions in footer.
- Footer Top
- Footer First Column
- Footer Second Column
- Footer Third Column
- Footer Fourth Column
- Footer Bottom Left
- Footer Bottom Right
- Footer Bottom Last
How to add content in footer
Navigate to:
Home 
Administration Structure Block layout
example.com/admin/structure/block
Place any existing block in any of the footer block region.