ref – https://www.thoughtco.com/past-participle-1691592

In English grammar, the past participle refers to an action that was started and completed entirely in the past.

It is the third principal part of a verb, created by adding -ed, -d, or -t to the base form of a regular verb.

The past participle is generally used with an auxiliary (or helping) verb:

• has
• have
• had

to express the “perfect” aspect. This aspect is a verb construction that describes events occurring in the past that are linked to a later time, usually the present.

To understand past participles, you first need to know how to make a verb past tense. To do so, add ed, d, or t, as in these examples that show the verb on the left and the simple past tense on the right:

Jump > jumped
Sleep > slept
Touch > touched

Turning these verbs into past participles is also simple.
Make the verb past tense and precede it with an auxiliary verb, as in these examples that list the simple past on the left and the past participle on the right:

Jump > have jumped
Sleep > have slept
Touch > have touched

In addition to the perfect aspect (or perfect tense), the past participle can be used in a passive voice or as an adjective.

The past participle are used in 3 situations:

• Perfect aspect
• Passive voice
• Adjective

Though they may seem similar, there is a difference between the regular past tense and past participle.

The regular past tense has only one part
Past participle always has two or more parts and generally requires an auxiliary verb.

An example of a sentence with a regular verb would be: I helped my friend.
You helped your friend at some time in the past, and completed it in the past.

The same sentence with a past participle verb would be: I have helped my friend.
You helped your friend at some time in the past and have completed it in the present. You may even help her in the future!