IMPORTANT § 6AB: if you are not on a monthly payroll you ARE NOT an employee. If you send invoices working for a company you are self-employed.
IMPORTANT § 6B: Invoicing foreign clients (with a CZ trade license) IS NOT foreign Employment (do not tick the § 6B box but § 7 instead).
IMPORTANT § 6AB+ 7: If you are employee and have a CZ trade license - even if you made no money with your TL, overviews for social security and health need to be filed, so also in the case of no revenue with your TL, tick the § 7 box.
IMPORTANT § 7 /10A: LLC / Foreign Business Profits may fit in §7 or §10 - depending whether you have a CZ trade license and whether the foreign business is (considered) sole proprietorship (file in §7 with active CZ TL) or an independent legal entity with a dividend payout (usually file in §10A).
IMPORTANT § 8: regular small interests on personal bank accounts are usually deducted at source and DO NOT need to be entered in §8.
IMPORTANT § 9: rental income from abroad IS NOT taxed in Czech Republic
IMPORTANT § 10B: vested shares should be declared in the year they were vested. Selling of shares, payouts from investment portfolios and profit on property may be tax-exempt.