if you please; if you don't mind; when you're ready; if you want; if that's alright with you
Polite conditional phrase used to make a request or suggestion in a considerate way. Often softens a proposal or invitation.
If you'd like, how about some tea?
If you don't mind, please write your name here.
よろしければ is a more formal, polite way to say 'if it's alright with you', while できれば is the everyday casual equivalent focusing on feasibility.
The conditional form of the polite adjective 宜しい (よろしい), which is the formal equivalent of 良い (よい). The phrase literally means 'if it is good/all right'.