So, I crashed my car and

I’m looking into repairing my vehicle primarily on my own, but the damage to the front end is pretty significant. There’s a bar in the front of the vehicle that looks like the front part of the frame. What is it called? It’s a welded on portion of the frame, and it was badly damaged, so I was hoping to look into removing & replacing it.

Your car has no “frame”…It’s unibody construction, a welded-up sheet-metal structure. If this structure was deformed in an accident, special tools, skills and equipment are needed to repair them, including specialized welding equipment and skills…

It’s not really a DIY project…

Caddyman is correct.
While there are many repair projects that a car owner can take on, repairs to the body (and very possibly to the chassis) of a “significantly” damaged unit-body car are not really feasible without the equipment and skills that a professional body shop has at its disposal.

Unless you have the skills, training, tools, and facilities for auto body repair, take the car to a body shop. This is beyond DIY for most people.

Can you take a photo of the bar?

Mounted to the unibody is a subrame that helps support the motor and drivetrain. It sounds to me like the part you’re alluding to is a transverse support member of the subframe. Without a photo it’s guesswork.

I agree with the others that unless you know what you’re doing this is likely beyond the capabilities of the Do It Yourself person. Straightening framework takes a pro with proper equipment.

Unless you make a habit of submitting claims, you should let your insurer hande the fix. They know who does good work in your area and what it should cost. In fact, the insurer will tell the shop what they will get for the repair.

You are describing the sub frame/engine cradle or the lower tie bar which is part of the radiator support.

AND

do not attempt to repair yourself, let a shop do it.