You can edit the Partner Capital information for each partner in the Business Information section of TurboTax Business.
Select the Business Info tab near the top left of the screen. Then select Partner/Member Information. You can then select to EDIT the partner. You will be brought through several screens, but should eventually be brought to a Partner Capital screen where the beginning and ending capital balances are entered, plus any contributions from or distributions made to the partners. You will need to edit each partner capital screen individually for each partner. See the sample screenshot attached.
