Not everyone would want to leave the design part of uniform patches upon third parties as some people would want to play a bigger role in designing their own stuff. So the question that you may want to ask yourself would be whether it would be possible at all for you to make your own patch for your uniforms.
If you are not a professional and you are doing it for the first time then unfortunately you might never be able to do it on your own as you will require help from a professional who could assist you with the entire process.
However, there are certain companies such as Houston Embroidery Service who could assist you in making your own patch by providing you with all the necessary resources in order to have a bigger say on what you would want the final outcome of your uniform patch to be like.
If you get multiple designs including those that are popular among people from your profession you will be able to choose something appropriate from a huge list that you get access to. It would then depend upon your own creativity on how you customize things to make your own patch.
So yes you can definitely make your own patch for your uniforms if you have access to all appropriate resources which is something that you can usually do with the help of an established service provider.