How can I add the outline of Europe countries in this figure in R?

Here is my code to create this distribution map of Europe in R. So how can I add the outline in this figure to divide different countries and also add the countries’ names in relevant regions?

>library(sf)
>library(rgbif)
>all <- st_read('~/Desktop/amre2935_supplementary_atlas_s4_shapefiles_reptiles/allcountries_rep.shp')
>all <- subset(all, select='emy_orb')
> summary(all)
    emy_orb                geometry   
 Min.   :0.0000   POLYGON      :5453  
 1st Qu.:0.0000   epsg:4326    :   0  
 Median :0.0000   +proj=long...:   0  
 Mean   :0.1423                       
 3rd Qu.:0.0000                       
 Max.   :1.0000  
> all
Simple feature collection with 5453 features and 1 field
geometry type:  POLYGON
dimension:      XY
bbox:           xmin: -14.3358 ymin: 34.30561 xmax: 66.7329 ymax: 71.65074
geographic CRS: WGS 84
First 10 features:
   emy_orb                       geometry
1        0 POLYGON ((-14.3358 47.4027,...
2        0 POLYGON ((-13.6733 47.39694...
3        0 POLYGON ((-13.01106 47.3873...
4        0 POLYGON ((-12.34923 47.3739...
5        0 POLYGON ((-14.29924 50.1012...
6        0 POLYGON ((-14.30573 49.6515...
7        0 POLYGON ((-14.28579 51.0004...
8        0 POLYGON ((-14.29261 50.5508...
9        0 POLYGON ((-14.2788 51.45003...
10       0 POLYGON ((-14.32421 48.3023...
>pal <- c('grey', 'red')
>plot(all['emy_orb'], key.pos=NULL, reset=FALSE, main='All Countries', pal=pal, border=NA)