best and attractive format of application to DM.

Any suggestion depends upon the tender conditions and the conditions of contract, if any. Any how, you can make representation to the competent authority of the adverse situation because of unforeseen circumsatnces beyond your control.

The authority that finalized tenders and under whom you are operating is the competent authority.  Every fact is needed in the form of data.  Collect data of last year's actual charges and this year charges month-wise, the actual lockdown period, and pray for reduction of the contract amount proportionately based on per day contract rate.  This maybe your proposal and they may discuss and propose some other and both have to reach for a common remedy.   What is the total contract per annum and what works out for one day in a year, and add 30 days for the actual locking period?  The government itself is coming with proposals that landlords should postpone the rent and should not bring pressures.  Against this background, you can certainly get a relief.  As there is lock-in period and also vacation, most of the advocates have free time and you can provide them with much needed data and can get a draft for an amount not exceeding Rs.1,000/- from a best advocate in your town.

Approach concerned authorities (signitary to tender document) with a written memorendum.

What matters is not the attractiveness of the representation, but its effectiveness. What is attractive, need not be effective or evocative,