I assume you are referring to an LOI ... letter of intent. Spells out material terms and assumptions. Plenty of samples online; tailor to your transaction.
LOI's aren't used with single family homes, no need for them and they serve no purpose on s sfh, just make an offer.
@Fou Saelee I see it is your first post so welcome to BP
Tom and Wayne are both right. It is letter of Intent and is normally used on large commercial transactions. If you are trying to purchase a SFH, an experienced seller will know you are new and inexperienced.
If the property has been vacant for years a verbal offer is fine to get things started.
ALL that said they may be an example in the FlePlace under the tools tab above.