Has anyone used PO box to get green card?

For some reasons, I cannot send my green card to my physical address. I’m also planning to relocate but my green card will be sent before I relocate. So I need a safe mailing address. I don’t have a lawyer and my friend refused to help. So my last option is using PO box but I’m afraid if it is safe.. Has anyone used PO box as mailing address? Please let me know if you have any advice or recommendations.