Suppressing "# A Tibble <R> x <C>" and Column Datatypes

Hi, and welcome! Your question straddles the boundary between abstract enough to not need a reproducible example, called a reprex and those that do. In this case I used the following chunk to replicate your output

```{r code_chunk, echo=FALSE}
n <- enframe(4) %>% select(value) %>% rename(n = value)

which reproduces your output

A tibble: 1 x 1
1     4

The expedient approach is to assign the result of your code in the chunk, which leaves nothing for the chunk to output

# [within chunk]
n <- dailyGenerationQA %>% filter(sum_detail_diff > 20) %>% count()

And then do an inline reference to it outside the chunk.

`r n`

which will get you a bare 4.

This will take you only so far in formatting RMarkdown documents, however, and eventually you are going to want to familiarize yourself with chunk options, knitr options, kableExtra, pander and format for greater control over the appearance of output.