How to remove a payment field form a form?

How can we remove the payment part as we receive purchase order net 30 days

If I understood correctly, you want to remove a PayPal payment field from your form and use a Purchase Order payment field. 

To remove a PayPal payment field, select it inside of the Form Builder and click on Remove button. You can then add a Purchase Order payment field to the form. All product will be saved and automatically added to the form.

However, before deleting a field, I would suggest you to first download your data because data you collected with the PayPal field will be deleted from the submissions page of your form. 

How to Download Form Submissions as Excel/CSV/PDF

I can not delete pay pal says only one allowed.
*Warm Smiles,*
Michael Berginc
Guru Go Club
2529 Central Ave.
St. Pete, FL 33713
727-643-5051
*www.GuruGo.Club*
*Proud contributor*
*The Life Smiles Project*
*"Art for Hospitalized Children"*
*Ten Million Smiles...NOT ONE LESS!!*
*www.LifeSmiles.Life *
Confidential: This electronic message and all contents contain information
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Thank you for your help.
Now all of my products have disappeared. Im really mucking this up!!
Thanks
*Warm Smiles,*
Michael Berginc
Guru Go Club
2529 Central Ave.
St. Pete, FL 33713
727-643-5051
*www.GuruGo.Club*
*Proud contributor*
*The Life Smiles Project*
*"Art for Hospitalized Children"*
*Ten Million Smiles...NOT ONE LESS!!*
*www.LifeSmiles.Life *
Confidential: This electronic message and all contents contain information
from Guru Go Group Inc. which may be privileged, confidential or otherwise
protected from disclosure. The information is intended to be for the
addressee
...

Deleting the payment field will indeed delete all the products, it's not possible to keep the products only if you have used the "selling products" payment type. 

Now, if you need to have your products available through the payment integration and get rid of the PayPal configuration, then I would recommend you to use the purchase order integration instead, here is a guide that will help you adding it to your form: https://www.jotform.com/help/460-How-to-Create-Payment-Form-with-Purchase-Order 

I hope this helps.