Disclaimer: CoinTracker is provided for informational purposes only. This service is not intended to substitute for tax, audit, accounting, investment, financial, nor legal advice. For financial, tax, or legal advice please consult your own professional. The information on CoinTracker is subject to change without notice. All information is provided "as is." CoinTracker disclaims any responsibility for the accuracy or adequacy of any positions taken by you in your tax returns. Please see our full disclaimer.
Generally speaking, in the U.S., you will want — at a minimum a Form 8949 (Sales and Other Dispositions of Capital Assets) complete with your cryptocurrency transaction history. This is the form that CoinTracker will generate for US-based users. In addition a summary of your overall capital gains for cryptocurrency is provided in the "Capital Gains" section of the tax page which can be aggregated across all asset classes and then put on your Schedule D (Capital Gains and Losses), and then your Form 1040 (Individual Income Tax Return). Any income (from forks, airdrops, mining, or payments) will go on the "other income" line 21 of Form 1040 Schedule 1.
Additionally, if any of your cryptocurrency assets were lost or stolen, you will want to complete Form 4684 (Casualties and Theft — note this is only allowed before 2018). If you held $10,000 or more on a foreign exchange (non-US based) at any time during the tax year, you need to file a FBAR. If you held more than $75,000 on a foreign exchange (at any time during the tax year) or more than $50,000 (on the last day of the tax year), then you must additionally file a Form 8938 (Statement of Specified Foreign Financial Assets, a.k.a FATCA). If you underpaid your quarterly taxes for capital gains, then you will want to complete a Form 2210 (Underpayment of Estimated Tax by Individuals, Estates, and Trusts).