Abdulaziz Welcome to Microsoft Q & A Community Forum. Based on the information you provided, it sounds like the Basic pricing tier for Azure Web Apps would be a good fit for your needs. The Basic tier provides a good balance between cost and performance and should be able to handle the anticipated load of 700 to 1000 students submitting forms.
The Basic tier provides up to 3 instances, which should be sufficient for your needs. Each instance has 1.75 GB of RAM and 1 vCPU, which should be more than enough for your relatively light computational load.
In addition, the Basic tier provides auto-scaling capabilities, which can help ensure a smooth user experience during periods of high traffic. You can configure auto-scaling to automatically add additional instances when traffic increases and remove them when traffic decreases.
Finally, the Basic tier provides support for custom domains, SSL certificates, and deployment slots, which can be useful if you need to customize your application further.
Overall, the Basic pricing tier should be a good fit for your needs, providing a good balance between cost and performance while ensuring a smooth user experience.
For pricing information, refer this document : https://azure.microsoft.com/en-in/pricing/details/app-service/windows/