How do I feel comfortable talking about my accomplishments? Specifically on my resume, but also in general?

I’m an engineer. I have lots to talk about and can easily do it in my field, but my lack of confidence in talking about my accomplishments keeps me from applying for a major job role that I know I am well qualified for. I don’t know how to be confident in my accomplishments. I would much rather talk about what I’ve learned. I feel so pretentious talking about what i did.