Assuming what you want to do is recreate disks from disk images stored on your PC (or accessible from your PC), there are a few ways to go about this, all of which involve extra hardware in one form or another.
Connecting your Atari to your PC
A number of devices allow your PC to act as a “server” for the Atari; in most cases, this is used to provide virtual drives using the PC. These devices connect the SIO port of your Atari (or a daisy-chained SIO device) to one of the PC’s ports, and can be found by searching for “SIO2PC” — there are serial and USB variants, available ready-made or you can build your own (see fred_dot_u’s answer).
Once you a connecting device, software such as RespeQt or AspeQt will allow you to control the PC side of things. On the Atari, the PC appears as a disk drive. You can then mount disk images directly from the PC on the Atari, and either use them immediately, or copy them to physical disks.
Using an alternative disk “drive”
Instead of connecting a PC, you can also connect a drive replacement, which will allow you to store multiple disk images on a more modern storage device, typically an SD card. Search for “SIO2SD” or “SDrive” to find these, again ready-made or with instructions to build your own. Once connected, you can use the disk images in a similar fashion to that described above, either directly or copying them to floppes. The SDrive at least has a variant allowing daisy-chaining in the SIO chain.
In my experience, this is the most practical solution — it allows you to use your Atari without the annoyance of floppy disks and without requiring a connection to your PC either.
Writing floppy disks using a PC-connected device
This is probably the most expensive and least reliable option presented here, especially if you don’t already have an appropriate 5.25” PC floppy drive.
There are a number of USB floppy controllers which allow Atari disk images to be written to floppies. For example, you could use Keir Fraser’s Greaseweazle along with his Disk Utilities and Joe Allen’s Atari Disk Tools to write ATR images to disks.
In practice, as far as 8-bit Ataris are concerned at least, such setups are more appropriate for reading disks than writing them; it’s much better to write Atari disks with Atari drives.