The short answer
For most customer-service texts, include four things: who the message is from, the visit or account it concerns, the one useful action the customer should take and a reply route if something is wrong. Keep the wording factual. Do not promise an arrival time, replacement date or payment status that the live round cannot support.
A dependable evening-before reminder is:
Hi {{customerName}}, {{businessName}} plans to clean your windows on {{date}}. Please leave any required access clear and gates unlocked. If there is a problem, reply to this message. Thank you.
Replace the double-braced fields from current customer and Planner data. Square-bracketed wording in the examples below is a decision for the cleaner to complete before sending.
