Yes, the e-vignettes are only linked to the vehicle's license plates and therefore you can purchase any e-vignette for other persons.
Please make sure you enter the correct license plate details and vehicle registered country.
Related articles:
Can I buy a Slovenian motorway vignette on weekends and public holidays?
What different types of the Slovenian motorway e-vignette are available?
How is the Slovenian vignette checked?
Penalties for wrong vehicle details given (e.g. wrong toll class)