What is the most efficient way to achieve " Separate values in a column of tibble and then create a new column and place the values there?"

Question

I have a tibble in R as below

tic
# A tibble: 111,523 x 3
IncidentID Brief Description    Category
1           This is an example   Example

#Now i want to unnest tokens and create a new tibble as below:
IncidentID  Data                   Category
1           this, is, an,example   Example

#When I did it using group_by()
IncidentId   Data               Category
1            this               Example
1            is                 Example
1            an                 Example
1            example            Example

I am a newbie in R. Please suggest me a way that is most efficient.