So many ways, depending ..
Assuming this is in Edit mode, and these are one-off parts already measured to fit a hole in the existing mesh, aligned to the world as shown, you could:
- Set Snap to 'Vertex, Active'
- Select the whole part, and in Vertex Mode, make one of its bottom right vertices active
- ShiftDX duplicate the part, snapping the rear vertex of the duplicated part to the corresponding front vertex of the existing one
- ShiftR repeat the operation until the hole is filled
- With all selected, AltM > 'By Distance' merge coincident vertices.
BUT.. this whole process seems a bit topsy-turvy, since you would already have had to measure up the part, somehow? Going back a couple of steps..
- In Edge Mode, Right-click > 'Subdivide' the opposing edges, adjust the cuts to 4
- I inset the five new faces, with the tool set to 'Individual' and 'Depth' adjusted to raise the inset faces to the desired distance
- Make tweaks afterwards?
If you had hundreds to do, or reasons to do this non-destructively, you could temporarily split the part off into a new object, and use an Array modifier, before rejoining into one object..