In vyapar, go to Menu, click on Backup/Restore. In the drop-down, you can find options such as Auto Backup, Back up to phone, Backup to e-mail, Restore backup. Select the option from the drop list as per your preference.
For instance, select the Backup to e-mail, you will receive an email that contains the backup file of vyapar.
Download the vyapar file( it has the extension of .vyb). Then convert the .vyb to a zip file by using rename option.
Example: demo_27-04-2019_18.01.25.vyb(Vyapar file) rename this file as demo_27-04-2019_18.01.25.zip
Now extract the zip file, you file will have the extension .vyp (demo.vyb)
Again rename the demo.vyb file as demo.sdb
In myBooks, Goto Settings > Business Settings > Preferences > Import Vyapar
Choose the file with an extension of .sdb then click on validate. Once the file validated, click on submit option to import your data to myBooks.