Error Code -36 while transferring photo library to external hard drive

MacOS Extended (Journaled) alone does not suffice, if one if the drives is formatted also case-sensitive. Both drives should be formatted without the case-sensitive option. And your external drive must not be used by Time Machine. Try to enable the "Ignore Ownership on this volume" option, if you have not yet done so. That will prevent permission and file ownership errors.

An error -36 can also be caused by incompatible filenames - filenames that are too long or contain ctrl-characters. This can happen, if you imported image files from third-party applications, that write illegal characters into a filename.

If all fails to copy the library to your external drive, you have two options:

• The easy way out would be to use cloning software like Carbon Copy Cloner or Super Duper to copy the library over. But this way the unreadable files will remain dormant in the copied library and may be causing problems later.
• You can also create a new folder on the external drive. Name it "Photos Library Copy", without any filename extension. Then open the library package on your system drive by ctrl-clicking it and using "Show Package contents". Now copy each subfolder individually to the new folder on your external drive.
• If a subfolder fails to copy and you get again the -36 error, check how far the copy succeeded and then look, which item should have been copied next and failed. Skip it and copy the remaining items. This is the advantage of copying the subfolders individually. We can check, where the copy failed and detect the culprits.
• Once you copied everything that can be copied, append the filename extension ".photoslibrary" to the name of the copy. The icon should change to the Photos Library icon. Now double click the copy to open it in Photos. Can this copy be opened in Photos and does it work?

See the article https://support.apple.com/en-us/HT204484

As a user tip: How to avoid the Error -36 when copying a Photos Library - Apple Community

What format is the drive and how are you connected to it?

The drive was formatted to MAC

There is no such format. It needs to be formatted Mac OS Extended (Journaled) or AFSP