Final answer:
The correct verb form is 'envío'.
Step-by-step explanation:
The correct verb form to complete the sentence would be envío.
The pronoun 'Yo' ('I' in English) is the subject of the sentence, and it refers to the action of sending emails. The verb 'enviar' means 'to send', and 'envío' is the correct form of the verb in the first-person singular form.
For example: Yo envío muchos correos electrónicos a mis amigos. (I send many emails to my friends.)
Learn more about Spanish verbs