Sample embedded signup form to collect basic information for a donation. See https://help.salsalabs.com/hc/en-us/articles/114094159854#forward-to-a-donation-page for more info.

sample-embedded-donation-form.html

  <fieldset>
    <legend>Donate here</legend>
    <form action="[[DONATE_PAGE_KEY]]" method="POST">
      <input type="hidden" name="object" value="supporter" />
      <input type="hidden" name="organization_KEY" value="5881">
      <p>
        <label for="first_name">First Name</label>
        <input id="id" type="text" placeholder="First Name" name="First_Name" />
      </p>
      <p>
        <label for="last_name">Last Name</label>
        <input id="id" type="text" placeholder="Last Name" name="Last_Name" />
      </p>
      <p>
        <label for="email">Email</label>
        <input id="id" type="text" placeholder="Email" name="Email" required/>
      </p>
      <p>
        <label for="street_1">Street 1</label>
        <input id="id" type="text" placeholder="Street Address" name="Street" />
      </p>
      <p>
        <label for="city">City</label>
        <input id="id" type="text" placeholder="City" name="City" />
      </p>
      <p>
        <label for="state">State</label>
        <input id="id" type="text" placeholder="State" name="State" />
      </p>
      <p>
        <label for="zip">Zip</label>
        <input id="id" type="text" placeholder="Zip" name="Zip" />
      </p>
      <p></p>
      <p>
        <label for="amount">Amount</label>
        <input type="number" name="amount" value="50.00" />
      </p>
      <p>
        <label for="submit"></label>
        <input id="submit" name="submit" type="submit" value="Donate!" title="Click here to donate." />
      </p>
    </form>
  </fieldset>