Tax preparation is the process of preparing tax returns, often income tax returns, often for a person other than the taxpayer, and generally for compensation. Tax preparation may be done by the taxpayer with or without the help of tax preparation software and online services. wikipedia.org

Tax law is an area of legal study dealing with the statutory, regulatory, constitutional, and common-law rules that constitute the law applicable to taxation, which is the method by which the government levies on economic transactions. wikipedia.org

Xero is an online accounting software product for small and medium-sized businesses, as well as for personal finance. The product is sold by subscription (a distribution model commonly known as Software as a Service or SaaS) requiring the payment of a monthly fee. wikipedia.org