How can we use Append Data to a Field.

Use Change Data Value, include the current value as a token in the New Value box.

   My Field  → {{lead.My Field}} new data

Please help me to understand more clearly, have confusion that how it will work

I had this issue. I had a Marketing Comments field that would continually get overwritten and I wanted to maintain the historical data for our SFDC records. I also wanted to include the date of the new information. To solve this I created a second field and used a trigger flow step and global tokens.

Fields used:

Original field: Marketing Comments

New field: Form Field Marketing Comments.

Flow steps: If "Data value change" is (form field marketing comments) then update (Marketing comments) to: {{system.date}} {{Lead.Form Field Marketing Comments}} | {{Lead. Marketing Comments}}

What this does is it keeps the original data in the field Marketing Comments with the lead token {{lead.Marketing Comments}} and appends the new information in the field Form Field Marketing Comments via the lead token {{lead.Form Field Marketing Comments}}. An example of the format of the updated field would look like:

   July 30, 2018 Requesting quote for ABC in quantity 123 | February 17, 2018 Please provide additional information for your widget | December 5, 2017 I would like to get lead time on item Y.

Does that make sense?