Building POS Like Apps

Hi there, I sell fishing equipment. 2 methods of orders. 1. From FB / Insta They will PM us, list what they want. We check stock & calculate total. Then we give our local bank account no. They make payment. We verify by login to our bank. We pack their orders. Send to courier. 2. Walk in They tell what they want. We calculate total. We record the details in receipt manually. We tell them the total. They pay using cash or online transfer. THE PROBLEMS NOW The problem I have is to record sales both online & offline. Have hard time to keep track stock because I do inventory manually. I have hard time with staffing because all works in done manually and unable to do anything if person in charge goes missing. So, I want to automate all these by using POS screen apps. Self service style. Step 1: They must register, verify account, add necessary details like Name, Shipping Address, Tel No. Then they can order using POS lookalike system. They click to add products they want to buy on any device (android/iOS). They verify the orders & make payment by using online transfer or ATM Machine or Paypal. Once made the payment they will need to provide proof of payment by screenshot or pdf file. Step 2: We admin will verify their orders. Print their details like Name, Address & Tel no like Lazada or Shopee style. Ship to them. Done for online orders. Step 3: For walk in customers They can repeat in step 1. They can choose to pay using cash or online bank transfer or paypal (fund transfer or credit card). Any mode of payment they choose we can verify by accepting the payment. Example if they pay using cash then when they submit the orders, we will approve it once payment accepted. If Admin have to do all the Step 3 then admin should be allowed to choose existing customer if they already have the account. If not they need to register. Above are the steps we plan to do. But of course all the logics you need to figure it out. ------------- As admin we need to do all these: 1. Print customer label to stick on the packaging for shipping purpose. 2. Add unlimited products by categories, varieties like colors, size, weight, SKU, etc 3. Set shipping rate for local shipment. 4. Set shipping rate manually for international shipment. 5. Download & print by date, daily, weekly, monthly sales report. 6. Download & print daily sales for shipping purpose so details like Name, Address, Tel no, products ordered should appear. 7. Do inventory like set minimum level stock level, notification for out of stock products, and some other relevant functions. 8. Customer order history. 9. Apply discounts. 10. Coupon. 11. Separate Online Customers or Walk in Customers. 12. Print receipt using any type of printer like Thermal printer. 13. Set product prices, sales prices and stock quantities. 14. Create users like Cashier for Walk in Customers, Online Orders for Online Customers. 15. Do refund. 16. Accept partial payments. 17. Add notes to orders. 18. FILTER BY UNPROCESSED ORDERS. 19. Admin mark the orders by Pending, Processing, Pack, Shipped. Buyers should be able to see the progress. 20. Payment approve notifications for customers. 21. Get push notification for order. For ideas: 1. [login to view URL] 2. [login to view URL] 3. [login to view URL] 4. [login to view URL] 5. [login to view URL] 6. [login to view URL] . I'm interested with this idea. Where they have the idea of The Walking POS system. Basically, we just want to simplify everything. Its hard doing manual orders because sometimes too many things going on at our facebook/instagram until we face issues like lost orders. So, if we can force the buyers to use apps and buy we will have their records. Please dont bid if you cant do. Thanks