Hi Kiran,
PO Tables:

PO_HDR
PO_LINE
PO_LINE_SHIP
PO_LINE_DISTRIB
PO_VAL_ADJ
PO_APPROVAL
PO_LINE_MATCHED

Staging tables:
PO_HDR_STG
PO_ITM_STG
PO_DISTRIB_STG

General Ledger Tables
PS_LEDGER: The general ledger data table.
PS_JRNL_HEADER: Stores general ledger journal header data.
PS_JRNL_LN: Stores general ledger journal line data.
ps_combo_rule_tbl: Stores ChartField combination rules.
ps_combo_group_tbl: Stores ChartField combination groups.
ps_combo_data_tbl: ChartField Combo data table.
ps_bu_led_comb_tbl: Business Unit CharField Combos for Ledger.
PS_GL_ACCOUNT_TBL: GL Accounts table.
Accounts Payable/Voucher Tables
PS_GRP_AP: Stores AP control groups.
PS_VOUCHER: AP voucher header table.
PS_VOUCHER_LINE: AP voucher line.
PS_DISTRIB_LINE: Voucher distribution table.
PS_PAYMENT_TBL: AP disbursements table.
pymnt_vchr_xref: Voucher Scheduled Payment.
PS_RT_RATE_TBL : Market Rate Data Tale. There is also the market rate default view RT_DFLT_VW.
PS_VCHR_ACCTG_LINE: AP accounting entries.
Voucher Build Staging Tables
PS_VCHR_HDR_STG
PS_VCHR_LINE_STG
PS_VCHR_DIST_STG
PS_VCHR_PYMT_STG
ps_bu_dfhi_opt_vw: Used by voucher build for the defaulting process.
VAT (Value Added Tax) Tables
PS_TAX_CD: Stores VAT Tax codes.
PS_TAX_AUTHORITY: Stores VAT Tax codes percentage rates.
Vendor Tables
VENDOR: Stores vendor related information.
VENDOR_ADDR: Vendor address related info.
VENDOR_LOC: Vendor locations.
VENDOR_PAY: Payment processing specifications such as payment method, payment handling code, bank code and so forth.
VNDR_ADDR_SCROL: Index to address table.
VNDR_CNTCT_SCR: Index to contact table.
VNDR_LOC_SCROL: Index to location table.
VENDOR_ID_NBRS: Additional ID numbers (Dun & Bradstreet numbers).
VENDOR_ADDR_PHN: Vendor phone numbers.
VENDOR_CNTCT: Vendor contacts.
VENDOR_CONVER: Vendor converstaions.
VENDOR_INVOICE: Stores vendor invoice related flags.
VENDOR_TYPE: Vendor type codes.
VNDR_BANK_ACCT: Vendor electronic payment information.
VNDR_CNTCT_PHN: Vendor contact phone numbers.
VNDR_IND_CLASS: Vendor Standard Industrial Classification (SIC) codes.
VNDR_URL: Vendor website address.
VNDR_VAT_RGSTRN: Vendor VAT information.
VENDOR_WTHD: Witholding data.
VENDOR_WTHD_JUR: Witholding type.