Hello,

1.       Grouping of Contacts: Many of our customers are part of group companies (or group). How to assign various groups to the contacts?

While creating a new contact, you can create it inside the existing contact, under the "Cotact&Addresses" tab.

2.       There are various types of contacts other than Individual and Company. For eg. LLP, Society, NGO, Partnership firm, HUF, PSU, Govt Dept etc. How to mark such Contact type in each contact. Individual contacts also have other related categories, for eg. Director, Shareholder, Partner, Designated Partner, Accountant, Manager etc. How to mark such Contact Sub-type in each contact

You can use the "Tags" feature in the contact for the same.

3.       Hiding Contacts from Specific user:  Currently my all users are able to view all the contacts of the organization. How to assign the contact View to Specific user so that he can view only related/assigned task and related/assigned contacts only. Further How to restrict user from downloading entire contact list?

Assign the Salesperson for each contact. Then with the help of access rights, you can manage this.

4.       Contact v/s task management: Currently I am able to view the task list containing the name of Contacts assigned to the Tasks. However, I am unable to view the Contact List containing the list of tasks assigned to the Contacts. How to configure the same?

In the Tasks, use the "Group By - Contacts". It will help you to group the tasks by contacts.

5.       Is there any process to Activate and Deactivate specific Contact?

You can use the Archive or Unarchive feature in the contact (Actions)

6.       Showing only Specific tasks to Specific User :  If I am sharing/assigning the project to a Specific User, he is able to view all the tasks of the project. If I want to make him view only specific task out of many tasks of the project then how to configure it?

By default, you can use the "My Tasks" filter. Otherwise, you can do some customizations for that