From what I can see you have some typos/syntax issues, e.g. an extra ")" at the end of the geom_bar()
line, and no stat = "count"
in your geom_text()
. Here is a reproducible example using the mtcars dataset which illustrates a potential solution:
library(ggplot2)
ggplot(mtcars) +
geom_bar(aes(x = cyl)) +
geom_text(stat = "count", aes(x = cyl, label = ..count..),
vjust = 1.5, colour = "white", size = 3.5)

Created on 2021-07-28 by the reprex package (v2.0.0)
I can't test the solution out with your data as you haven't provided any (please see How to make a great R reproducible example), however my guess for your situation is:
ggplot(MP1) +
geom_bar(aes(x=TBI), fill="dodgerblue"))+
geom_text(stat = "count", aes(x=TBI, label=..count..), vjust=1.5, colour="white", size=3.5)
In order to create a stacked barplot:
library(ggplot2)
ggplot(mtcars, aes(fill = factor(gear), x = factor(carb))) +
geom_bar(position = "stack") +
geom_text(stat = "count", aes(label = ..count..),
position = position_stack(vjust = 0.5))

Created on 2021-07-28 by the reprex package (v2.0.0)