Unable to load pdf file from desktop to Books on MacBook Air

Hi All,

im new to this platform and this is my 1st time to use a community for advice so maybe someone can give some advice to a nipper like me!!!!

Im having difficulty with uploading / loading pdf files from my MacBook Air to the Books app ( this has only been happening this year), I used to be able to add several files at a time without problem, organise into my folders all from the desktop and see the actions on both my iPhone / iPad. However if I upload files from my iPhone to books works without issue.

Now it’s becoming ver frustrating and costing me a lot of time. I rely on the books app and it’s a great bit of software.

Can anyone help me.

thx Muz