How to show rental expenses in sole proprietorship business?

Yes, you can show the rent as an expense and claim deduction. You should possess a rent agreement/deed and duly acknowledged rent receipts for ready reference in case any information is sought. 

If Your trade license contains your professional address which you intend to change now then you must apply for change/amendment .

@ Ruchi Thank You. Regarding the trade license, is it mandatory to change/amend this new rented space as the office address? Will there be any legal/tax implication if I do not update my trade license?

There are no tax implications but definitely you should update your professional address in your trade licences because licensing authorities have their own rules and regulations regarding this. Hence you might face difficulties and penal consequences.