Block diagram using latex

Question

How to make a simple block diagram using latex e.g. I would like to make a block diagram as shown in pic.

Answer 1

This is just to try out something "new": pass styles from a foreach loop. Works. Only need the /.expanded key. Technically this should answer your question. Whether or not it answers the question you wanted to ask, I do not know, working crystal balls are rare these days.

\documentclass[tikz,border=3.14mm]{standalone}
\usetikzlibrary{chains,decorations.pathreplacing}
\begin{document}
\begin{tikzpicture}[node distance=.8cm, start chain=going right,font=\sffamily,
    pft/.style={rectangle,draw,thick,text width=8em, minimum height=3em,text centered,on chain},
    every join/.style={-latex, thick}]
 \path foreach \X [count=\Y] in
 {{draw=none},{pin=above:text},,{pin=below:text},,{pin=above:text},{draw=none,align=left}} 
 {node[join,pft,style/.expanded=\X] (node \Y){text}};
 \begin{scope}[decoration=brace,thick]
  \foreach \X in {2,3}
  {\draw[decorate] ([yshift=-1ex]node \X.south east) -- ([yshift=-1ex]node \X.south west)
  node[midway,below]{text};}
 \end{scope}
\end{tikzpicture}
\end{document}