Blender 4.0 - Texture slot has moved to a new location
This version does not have "texture slots." How can I create multiple layers?
Blender 2.8 - How to delete a texture slot in Texture Paint mode ...
In the material/texture tab, make sure you have a texture slot with the image loaded, set to UV layout (instead of say obj coord), and linked to color, as in first reply.
::slotted() - CSS | MDN
The Exposure Metering Mask gives artists an optional texture slot to control the influence of auto exposure for the whole screen, where each pixel is weighted in importance by the assigned texture mask.