What are the four requirements for an electronic signature to be valid?

The four requirements for an electronic signature to be valid under US law are: intent to sign, consent to do business electronically, attribution linking the signature to the signer, and a retainable record each party can keep.

Intent means the signer meant the mark as a signature. Consent is usually a checkbox or clause agreeing to electronic dealings. Attribution is the evidence trail, email, IP, login, tying the act to the person. Retention means both sides can store and reproduce the signed document.

A handwritten signature can absolutely be electronic: sign on a touchscreen, or scan and apply it, and it qualifies. The short list of exceptions, wills, some family-law and court documents, still wants ink. For business contracts, any signing flow that captures the four elements is solid.

Contract software with built-in signing captures all four automatically.