SaaS Sales in Paris

I am very glad to join this community to learn and share opinions regarding Saas Sales.
I am a Master’s Student studying in Marketing in Paris, France. I am very curious about SaaS Sales and I wish that I could work in a saas company beginning as BDR or SDR in 2022.
I would like to take the opportunity to ask a question, what is the difference between BD and Sales in a SaaS company?

Thank you in advance for all your help!