You are always required to have your own inventory, with enough detail to determine the fair market value (at a minimum, a brief description and the condition (good or fair -- you can't claim any value for items in poor condition unless you have a signed appraisal). You also need a receipt from the charity although this does not need to be as detailed as long as you have your own detailed inventory. Then, determine the fair market value on your own -- you might use the prices charged by the thrift store for your items. For better quality items, you might use consignment shop value or an online marketplace like Thredup.
You can enter a single donation per day for all items donated that day. You do not need to list each individual item on your tax return. From the item donation menu, choose "used clothing and household goods", and enter your value. On the next page you can give a more specific description of the items. Keep your inventory and receipts for at least 3 years in case of audit.
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