According to the National Conference of State Legislatures, 34 states have laws that require voters to show identification when voting.
Trump said many Americans need a picture ID to make purchases among other things, but not at the polls.
Shoppers do need IDs to buy alcohol, some medicines and cigarettes.
Mr. Trump visited Florida to campaign for Rep. Ron DeSantis, who is running in the August 28 GOP primary for governor against former congressman and Florida agriculture commissioner Adam Putnam.
Democrats "don't want to give Trump any victory", he said.
Federal judge blocks 3D-printed guns from going online
They fear terrorists could make their own firearms "in just a couple clicks", according to a tweet from Everytown for Gun Safety. Under the settlement, the Trump administration will allow downloadable guns for unlimited public distribution in any form.
President Trump boards Air Force One at Andrews Air Force Base in Maryland for a trip to Tampa to attend a rally on July 31.
"People say Ron is all-Trump, but he's really so much more", Mrs. DeSantis quips, as the camera pans to a child of tender age in a crib, wearing a Make America Great Again onesie.
The new ad is narrated by DeSantis' wife, Casey, who starts by reminding viewers that Trump has endorsed her husband in the August 28 Republican primary.
DeSantis has tied his campaign for governor directly to Trump, even teaching one of his two children to "build the wall" with blocks in a recent campaign ad.
The comment came as Trump was haranguing the crowd at Florida State Fairgrounds Expo Hall about what he said was the need to prevent voter fraud by requiring voters to present photo ID before being allowed to cast a ballot in United States elections.
"It's insane", he added, "but we're turning it around".