Formal:
* سلامت وي (Salamati wai) - This literally translates to "be healthy", but it is a common and polite way to say "be safe".
* حفظ الله (Hafiz Allah) - This means "May Allah protect you". It's a very respectful and common blessing.
Informal:
* ښه پاتې شه (Kha paati sha) - This means "stay well".
* سلامت (Salamati) - This is a shortened version of "سلامت وي" and can be used in informal situations.
Other options:
* د خطر څخه محفوظ (Da khatar cha mahkuf) - This means "safe from danger".
* خپل خيال وساته (Khapal khyal wsata) - This means "take care of yourself".
The best choice depends on the situation and your relationship with the person you're talking to.