Can a unit crest be designed for company level or does the company just wear a BN crest ?

The unit crests I have worn in my 22+ years of service were all BN level or higher. But, if you want to know if you can design your own, contact your BN S4 OIC to get their info/input. Also contact the Office of Heraldry to see if they know how to do this.

So, a CREST is for a regiment - Regimental Crest.
An INSIGNIA is for a unit - Distinctive Unit Insignia.

In SOME units, they are they same. These are mostly your combat arms. (When I was in 4-31 INF, I wore the 31st Infantry Regiment's Crest for both my DUI and my RDI). Other units, they are different. These are most of your combat support and combat service support units. (Once I crossed over to MI, I wore the Military Intelligence Regimental Crest, regardless of which unit I was in).

Insignias of ALL sorts are authorized and controlled by the US Army Institute of Heraldry (USAIoH). Yes, you can, *in theory* create a company level insignia; however in order to actually USE it for official purposes (such as wearing on Class As), it would need to be approved by the USAIoH, and good luck getting that to happen.

That does not, however, prevent you from using it for *unofficial* purposes, such as organizational T-Shirts or coins. I have a SFC O'Mally coin that I designed and purchased myself. It has my own "insignia" on it, with personal artwork. I can use that all I want, as a coin is not an "official" action.

Do you mean the Distinctive Unit Insignia (DUI)? If you want that created or changed your unit needs to go through the Office of Heraldry as MSG (Join to see) said.

If you're just looking for a unit logo that your unit uses and puts on COA's, t-shirts, and things like that your unit can do as you like so long as it doesn't violate any Army policies, i.e. gang related, racist, profane, etc.

My unit changed our unit logo during our last deployment and we put it on everything we could get away with. As for our DUI, we use our battalions.