moving photos to external hard drive and keeping original information

Couple of things:

1. Drag and drop does not get your images. It gets a preview of them - a sort of handy mid quality/mid size version, and metadata can be patchy. If you want to get best quality copies of your images use the file -> Export command.
2. The format is important because each format handles different metadata in different ways. It should be either formatted Mac OS X Extended, Journaled or apfs.

There are two kinds of metadata involved when you consider jpeg or other image file.

 One is the file data. This is what the Finder shows. This tells you nothing about the contents of the file, just the File itself. The problem with File metadata is that it can easily change as the file is moved from place to place or exported, e-mailed, uploaded etc.

Photographs have also got both Exif and IPTC metadata. The date and time that your camera snapped the Photograph is recorded in the Exif metadata. Regardless of what the file date says, this is the actual time recorded by the camera. Photo applications like Photos, Lightroom, Photoshop etc get their date and time from the Exif metadata not the file date.

When you export from Photos (whether by drag and drop or File ->Export) to the Finder new file is created containing your Photo (and its Exif). The File date is - quite accurately - reported as the date of Export. However, the Photo Date doesn't change. The problem is that the Finder doesn't work with Exif.

So, your photo has the correct date, and so does the file, but they are different things. You can edit the file creation date to match the Exif using a variety of apps, among them

https://www.publicspace.net/ABetterFinderAttributes/

I am trying to move photos from a Mac to a Seagate external hard drive. [...] the original file information (date created, time, etc.) is gone, and it's instead using today's date

Are you moving photos or the photos library? What format is the external drive (APFS, MacOS Extended or maybe exFAT that is not supported by the Photos.app)? Please describe the workflow in more detail.

What dates -- the file dates that Finder readily displays or the internal metadata dates that need somewhat more digging? File dates often change when moving files around but the more important internal metadata dates are preserved (unless some social media site like Facebook, WhatsApp etc has deleted them).

In addition to Matti Haveri's questions,

What do you mean by "move photos from a Mac to a Seagate external hard drive?" (Well, Matti asked this, too.) But do you mean that you are in Photos and you use File>Export, or do you mean that you drag and drop? or what? And...

• What OS are you using? You say 11.7 Big Sur in your signature, is that right?
• Do you synchronize an iPhone with iCloud Photos?
•    if so, do you have “Optimize Storage” checked in Photos’ Settings
• What models are your devices?
• Where does your Photos Library reside-- in the Pictures folder of your internal drive, or on an external drive? or on a network? on iCloud drive?