This is a compound tense, so two verbs are required: the main verb and the past participle of whatever verb you're using. The past participle does not have to agree in gender or number with the subject. The formula is:

HABER + PAST PARTICIPLE OF VERB

Some examples:

1. I will have finished. = Yo habré terminado.
2. She will have seen me. = Ella me habrá visto.
3. We will have cleaned the house. = Nosotros habremos limpiado la casa.

Irregular past participles:

Some past participles are irregular in all the perfect tenses.

1. For -er and -ir verbs, if the stem ends in a vowel, a written accent will be required.
2. Some verbs are irregular in the past participle form, so these verbs are considered irregular in the perfect tense. Here are the most common irregular past participles: