All gerunds end in -ing, but not all words that end in -ing are gerunds!

Gerunds are formed by the –ing form of the verb, but they act as nouns in the sentence. They can be the subject or the object in a sentence.

Students sometimes get confused between present participles and gerunds.
When you see an -ing word in a present or past continuous sentence, it is a present participle.

Example: I am writing my cover letter for the job I want.
The -ing word “writing” is a present participle here.

Examples of gerunds:

I love swimming (gerund as object)
Swimming is my favorite activity (gerund as subject)

Infinitives – “to” + the base form of a verb – can also be subjects or objects.
Examples:
to sing
to confess
to copy

It is not usually appropriate to put the infinitive as a subject at the beginning of the sentence because it seems old fashioned. Shakespeare wrote, “To be or not to be. That is the question.” You are not Shakespeare.
Instead of saying, “To learn English is a good idea.” We would generally say:
It is a good idea to learn English.

Infinitives can also be an object in a sentence.
Example:
They love to eat at restaurants.

Some verbs in English are always and only followed by gerunds and others by infinitives. Some verbs can be followed by either one.

When you make a list, you should use parallel structures that do not mix gerunds with infinitives.
Example:
He enjoys hunting, fishing, and hiking.
NOT, He enjoys huning, fishing, and to hike.

It is boring and horrible to memorize long lists of these, so just try to memorize the most common ones and learn the others by reading and watching movies and television shows in English that you enjoy.

Common verbs followed only by infinitives:
want
decide
afford
beg
refuse
seem
volunteer
wait
threaten
learn
demand
hope
intend
expect
plan
need
help
appear
tend

Common vebs followed only gerunds:
avoid
consider
enjoy
finish
quit
miss
advise
delay
mention
anticipate
complete
appreciate
practice
postpone
discuss
encourage
report
can’t help
resist
consider
keep
imagine
understand

Common verbs that can be followed by either one:
like
love
hate
begin
start
continue
attempt
forget
remember

Some verbs take both, but the meaning changes.
I stopped smoking means that I do not smoke anymore.
I stopped to smoke means that I paused to have a cigarette.

Note that we use some objects for a purpose ie for cooking, for smoking.
We use others in order to do something ie to cook, to smoke.
However, we never use “for to” + a verb in English to mean “for the purpose of.”
NEVER say, “I take my motorcycle for to get to the beach.”

However, there are a few  verbs that take “to” + verb + ing. “I look forward to meeting you, to speaking with you, to hearing from you” is correct. “I look forward to meet you” is WRONG.

I am used to waking up early.

She confessed to stealing the jewels.

You objected to retaking the test.

We are opposed to using violence.