Removing a wall comes with 2 possibilities:
Non-Load Bearing: Wall is parallel with framing above and does not support very much weight
Load Bearing Wall: Wall is perpendicular with framing above and carries Floor/Roof weight
Inspect the roof or floor framing atop the wall to determine which case you have:
Case 1 wall may be able to be removed without a new beam/post/footing but,
you will need a determination by an Engineer to be sure.
Case 2 will require engineering of a new Beam to support the framing above.
The beam will require support posts at each end and each post may require existing
or new concrete footings to support the concentrated weight transfer to the soil.
UNLESS...
the perpendicular framing is a clear span metal-connected wood truss designed not to bear on wall.
Also requiring consideration is the lateral strength of the building due to wind or seismic.
ALL walls in a building help restrict horizontal movement forces. A determination of
building safety needs to be established by an Engineer when wall strengths are removed.
Summary: An engineer can determine what is needed when removing a wall and should be
contacted for the most economical solution; Before you hire a contractor or draftsperson.