@Asrarshaik human readable form of invoice means the PDF/A-3(with embedded XML) for B2B invoices. For B2C invoices this could be a hard copy of Simplified Invoice issued to customers or or a soft copy in any format.
Regarding Retention amount, first you need to determine the tax position whether the retention amount will reduce taxable amount or not. There are no changes in VAT regulations regarding retention amount, tax position depends on contractual terms
If you take a tax position that retention amount will not reduce taxable amount, then you have two options for handling retention amount:
Option 1: Do not include any value towards retention amount and display this directly on the human readable form.
Option 2: Include retention amount as "Document Level Allowance (BT-92) with indicator ‘false’ and select VAT Category Code as Out of scope. Then in the tax subtotals, you have to include one more sub total for Out of scope category and enter retention amount as negative value (-10,000 in above example). As a result, VAT will be calculated on full invoice value (100,000 in above example) and Amount due for payment (BT-115) will be 105,000.