Where to put tracking code

General questions
1

According to the piwik documentation we are supposed insert the tracking code just before , However,
the piwik console says that "We recommend to paste it immediately before the closing tag.

Is there any reaon in the policy change? What are the advantage and inconvenience of different positioning?

2

Hello

we now recommend to place the code before </head>

3

can tell please where exactely, how to do , how can i open each page in the site and putthis code ? ; i cant see any page !