If you use the field services App, it has the feature to design and manage multiple forms (worksheets). 

You can quite easily design a form as well.

Field services > Configuration > worksheet templates

Create and save a new template and you would have the button "Design Template" to create the fields using studio

Tracking technical visits to clients is an important aspect of maintaining a good relationship with them and ensuring that their needs are met. The best way to achieve this in Odoo would be to create a custom module that allows your employees to fill out a predefined form with mandatory fields when they visit a client.

One way to do this would be to create a new custom model in Odoo to store the information collected during the technical visit. This model would include fields such as the date and time of the visit, the client's name and address, the employee's name, and any notes or observations made during the visit.

Another way is to use the existing CRM module, where you can create a new activity type "Visit" and link it to the client, in this way you can have all the information in one place, and you can track all the activities related to the client.

You can also create a custom form view that would be used to fill out the form, this form view could include fields such as date and time of the visit, client's name and address, employee's name, and any notes or observations made during the visit. This form could be accessed through a new button on the client's form view.

In either case, you would need to create a custom module that implements the new models and views and makes sure that the form is mandatory and the fields are filled out before saving the data.

We at DataInteger Consulting Services have more than 10+ years of experience Since openerp and now in Odoo development and we are confident that we can make your requirements work as per your needs. We have a team of experienced Odoo developers who are well-versed in creating custom modules and integrating them with Odoo to meet specific business requirements. Please feel free to contact us for more information.