After reading an article and, I wrote a summary.

At first , some Native Americans wore tattoos.

And tThen, U.S. explovrers came to America and they learned about tattoos.

They were serving in the Civil War and they got tattoos.

In 1960 to 1970, tattoos werethe 1960s, tattoos [ became / were becoming ] accepted by more people.

"The 1960s" is a much more common and natural way of referring to the years 1960–1970.

Because you are telling the history of tattoos here, "became" or "were becoming" sounds more natural than "were".

And inby 1980 , tattoos had become a popular.

ItTattoos can also bhave a history / have historical significance.

After reading an article and, I wrote a summary.

the and here is not needed

At first ,someHistorically, Native Americans have wore tattoos.

this is a little tough to fix, I want to say something like "In the beginning" to contrast.

And then, U.S.When explovrers came to America and they learned about tattoos.

America works here because it also refers to the whole continents.

Tattoos became more common among soldiers.

I think this is maybe the best sentence so far but another sentence connecting it would be helpful.

TheyMany soldiers got tattoos while serving in the Civil War and they got tattoos.

needs a to be rearranged a little to make sense.

In 1960 to 1970, tattoos were accepted by more peopleMuch later, around the 1960s, tattoos became more accepted.

1960s covers the time period you mentioned.

And inBy 1980 , tattoos had become a popular.

I'm a little mixed on this since I'm not sure how true I would say this is.

Sometimes it’tattoos are part of a costume. --

And it’sor a kind of modern art. --

It also be abut it's also history.

I would make these all into one sentence.