@amit, be sure you understand the purpose of each module in Manager before using it.
Expense Claims is for purchases on behalf of the company made by owners or employees with their personal funds. It is not the way to handle normal business expenses. An example would be that you, as an owner, happen to see a good customer at a restaurant by coincidence. You ask the customer to join you for dinner and pay for the meal as a form of marketing. That might be a legitimate business expense, but you might not have company cash or a company credit card with you. So you pay with your personal funds. Then you file an expense claim. Of course, I don’t know your operations, but I question whether a hotel receptionist would need access to that module.
You can issue a sales invoice for every customer, but the customer must be created in Manager first. Sales invoices are normally used when a customer buys on credit and will pay you in the future. An alternative is just to Receive Money.
Other possibilities include entering daily summaries rather than individual transactions. Of course, you will need some other software to maintain reservations, so you might find it easier to bill the customer from that package, presumably something optimized for the hotel business. At the end of each business day, you would enter summaries into Manager for accounting purposes.
Similarly, reception personnel might be given a cash box rather than access to the company accounts. They would be responsible to match the cash box to detailed receipts. Again, a summary would be entered rather than every transaction.