You can always find a summary of allowances here together with links to further information and clarification on certain allowances, but otherwise here they are in summary:
Personal Allowance (amount of earnings you can have tax free) – £11,500
ISA Allowance (amount available to invest over all types of ISA) – £20,000
Capital Gains Tax Allowance (amount of gains allowed before tax is due) – £11,300
Inheritance Tax Allowance (amount that can be inherited tax free, including property) – £425,000
Personal Savings Allowance (amount of savings income that is tax free) – £1,000/£500
Property Allowance (amount that can be earned by small property related deals) – £1,000
Trading Allowance (amount that can be earned tax free from minor trading) – £1,000
Rent a Room Allowance (amount that can be earned tax free from renting out a room in your home) – £7,500
Not all of these allowances apply to everybody so you should check that they apply to you before using this information for your personal tax affairs.