Currently, the customer is running the Atlassian cloud and would like to setup Jira ( server edition

[venkat]

1.What all questions shall be asked to prepare the proposal?

2. Elaborate on the technical solution and estimation

[Daniel Ebers]

Hi venkat,

this is actually a hot topic and need careful consideration.

I searched for the page which answers most of the critical questions (https://confluence.atlassian.com/cloud/compare-atlassian-cloud-vs-server-744721664.html).

I hope this helps you to guide the way for a first gathering.

When speaking of efforts is depends on the experience of the administrator who will be tasked with administration (and, maybe, governance).
When in doubt Atlassian Partners are ready to help with consulting, implementation and support (https://www.atlassian.com/en/partners).

Cheers,
Daniel