lot of modifications to do

Hello, so lets go one by one:
1. How to edit login page because i need to change the text, background colors.

At Pages, you will see login page, just edit it and change it 🙂 Extra styling changes needs to be done by css

2. I need to put background image in login page.

Same as 1

3. how to edit “our colleague” in dashboard.

Is a widget, find it at Appearance > Widgets

4. how to add calendar in dashboard.

You need a calendar plugin that ads that and place the shortcode in a widget or at the page

5. how can i give a user a capability to add an event.

It depends on what event plugin you use, some allows that and some dont

6. is it possible to add an attachment when user post something in activity as well in the live chat?

Not available right now for the chat, but for activity you can use activity plus plugin for buddypress

7. i cannot configure the location in my events. location not found. i tried to used maps.google.com but it gives me the same result. here is our location is google maps

https://www.google.ca/maps/place/Southern+Industrial+%26+Truck+Ltd/@49.667406,-103.895988,14z/data=!4m2!3m1!1s0x531f0f97a7b7f561:0xe422e894baf4729f?hl=en

Please share admin credentials so i can check it out

8. I cannot edit the settings in buddydrive it gives me an error. ‘Method not implemented” GET to /dashboard/wp-admin/options.php not supported.

Please share admin credentials so i can check it out

9. can you tell me how the buddydrive works. i upload a file then i set it to public in privacy preferences but the user cannot see the file in his end. i also try to restrict to a group but when i typed the group it gives me ‘ Please make sure to select a group using the autocomplete field.

Please share admin credentials so i can check it out

9. how can i give a user capability to upload his own file in buddydrive.

It should be available, please share admin credentials so i can check it out

10. In admin page, how can i set a to do list and all user will be view in their respective dashboard.

There is already a to do list plugin that ads it to the dashboard 🙂

11. is it possible whenever user post in site-wide activity and type in chat. it will gives all user a notification?

Not available without custom development

12. How to edit submit report page

At Pages > Submit Report > Edit / Is just a page with a form 🙂

13. How can i put events in calendar page.

Depends on what event plugin you use, which one you use right now? Some people use eventon and works fine

Hello, for 7, even google maps has it difficult to find the address, try maybe to put a more general address, first check if its found on google maps then add it there
8 and 9 might be related to the server, please try to contact your hosting provider about that 🙂