Use we'll in everyday speech and informal writing like texts or casual emails; write we will in formal contexts. Example: We'll be there by noon.
Pick we'll by who is reading
Texting a friend? We'll grab dinner after work. The contraction signals a casual message, and it sits right before the base verb grab.
Casual email to a teammate? We'll do better next time. In everyday workplace notes, the shortened form reads naturally and keeps the tone light.
Spoken plans with family? We'll never finish this job! Everyday talk almost always favors the contraction before a base verb like finish.
Formal writing instead? Use the full form there, so We will review the proposal rather than the contracted version.
One situation where the full form wins
Writing an academic paper, an official report, or a job application? Use the full form, as in We will review the proposal. Those formal settings usually call for we will, and the contraction we'll can read as too casual for them. In everyday speech and informal writing, the shortened form is the natural choice.