A: hello,
to create forms you can use the landing optimizer service, which allows you to create the forms with a drag and drop editor and to publish them easily, no technical knowledge is needed. You can check out these articles to know more regarding the service: https://mdirector.zendesk.com/hc/en-us/categories/200360951-Landing-Optimizer
To filter your contacts, you can use either standard and personalized fields or tags, that can be added to your contacts when importing (manually or via API) your contacts. Please, check out this articles to get more info:
https://mdirector.zendesk.com/hc/en-us/sections/200755721-Contacts-management
https://mdirector.zendesk.com/hc/en-us/sections/115001102685-Tags
LEt us know if you have more questions.
Best!