Can I give link to my new site from my different site?

Hey everyone,
I recently started a new project and I already have a domain that I was working on before but not anymore now. My new domain and my old domain both are using similar hosting and similar domain registrar with similar email accounts. so I wanna ask a question is it safe to give backlinks from my old to site to my new site? is it safe?

I don't see why that would be a problem Aditya.