Certainly,While both electronic books and paper books have several positive benefits, buttheir advantages, electronic books have more benefits than paper books.

Your sentence is grammatically correct, but a native speaker would probably not phrase it this way, because starting a sentence with "certainly" sounds very formal and a little old-fashioned.

Instead, it sounds more natural to restructure the sentence to start with "while".

You could also use "however", but you'd need to use two separate sentences, for example: "Both electronic books and paper books have their advantages. However, electronic books have more benefits than paper books."

ThHere are some reasons why electronic books are better than paper books.

Firstly, electronic books are lighter than paper books, so people can carry itsthem conveniently and p. People can buy new electronic books wherever they are.

There are two arguments here so for clarity it's best to split this sentence in two.

In addition, electronic books hasve become widespread, so there are many books that people can readtitles available.

This is a better-sounding structure that avoids using the word "books" twice in the sentence.

Secondly, electronic books can be read on the smartphones.

These days, almost all people have their own smartphones, so peoplethey don’t need to buy another device to read electronic books.

Your original sentence is not incorrect, but this is a more concise way of making the same point.

Also, electronic books can write notes and can remove themyou can write or remove notes in electronic books.

Finally, electronic books can givehave a positive influence on the environment.

As a result, ithis can reduce garbageslevels of waste.

"Waste" or "refuse" is more formal than "garbage" and sounds better in a written context.

For these reasons mentioned above, the advantages of electronic books overutweighted the downsides.

Surely,While paper books have the ownir advantages but, people need to shifting to useing electronic books.

Electronic books have several positivemany benefits

Benefits are inherently positive.

Certainly, both electronic books and paper books have several positivemany benefits, but electronic books have more benefits than paper books.

I think "many" better suits your usage here; "several" makes it sound more like you're about to list what these "several benefits" are, whereas here you seem to be going for something more general for this introductory sentence.

Firstly, electronic books are lighter than paper books, so people can carry itsthem conveniently and people can buy booksbuy them wherever they are.

Some things:
1. When "so" is used to connect two independent clauses showing a cause-and-effect relationship (in that order), it is generally considered appropriate to add a comma. "X so Y" without a comma is used in, for example, "I came so that you wouldn't be lonely." Notice that this is a different kind of usage.
2. The antecedent is "electronic books," so "its [sic]" is not appropriate. Be aware of pronoun-antecedent agreement.
3. Because "people can buy books wherever they are" is an independent clause, it would generally be considered appropriate to add a comma before the preceding "and." However, in this case, I think just removing the "people" improves the flow of the sentence.

In addition, electronic books has become widespread, so there are many books that people can read electronically.

Secondly, electronic books can be read on the smartphones.

Passive voice constructions are formed with a be verb + past participle.
"Smartphones" does not take a definite article because you are not talking about some specific set of smartphones, you are just talking about them in general.

These days, almost all peopleveryone haves their own smartphones, so people don’t need to buy another device to read electronic books.

Also, with electronic books can write notes, you can easily andd cand remove themnotes.

1. Electronic books are not the things adding and removing notes, so that cannot be the subject.
2. "can X and can Y" are usually more fluently expressed as "can X and Y"
3. Stylistically, I consider "add" to better mirror "remove" than does "write" (you could, for instance, say "write and erase")
4. You can add and remove notes with paper books as well, it's just more difficult.

Finally, electronic books can givhave a more positive influence on the environment.

You "have an influence" as opposed to "giving influence."

As a result, ithey can reduce garbages.

Pronoun antecedent agreement
Garbage is a mass noun.

For these reasons mentioned above, the advantages of electronic books overutweighted the downsides.

"Overweight" is an adjective meaning fat

SureUndoubtedly, paper books have their own advantages, but people need to shifting to usereading electronic books.

Surely -> undoubtedly usage
Inappropriate use of the definite article
Comma before coordinating conjunction connecting independent clauses
"Need to shift to using," not "Need to shifting to use"