How to add/update product reorder quantity options using import?
Step 1:
Go to Products > Products.
Step 2:

From "Import" menu, click on "Products".
Step 3:

Choose your import file to upload.
Tick on "Overwrite existing Item data".* (Note: This will overwrite existing item value)**
Click "Upload" button to import the file.
Fields require: (Case sensitive)

sku
min_quantity
max_quantity
reorder_quantity
Note:
All fields header are in lower case.
Do not leave any column empty, all column require value, else it will cause error.

Go to Products > Products.
Step 2:

From "Import" menu, click on "Products".
Step 3:

Choose your import file to upload.
Tick on "Overwrite existing Item data".* (Note: This will overwrite existing item value)**
Click "Upload" button to import the file.
Fields require: (Case sensitive)

sku
min_quantity
max_quantity
reorder_quantity
Note:
All fields header are in lower case.
Do not leave any column empty, all column require value, else it will cause error.
Updated on: 15/01/2020
Thank you!