Can you add keywords into the title tag and/or h1 after indexing or will this trigger a penalty?

Selected answers from the Dumb SEO Questions Facebook & G+ community.

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  John Pitcher: Can you add keywords into the title tag and/or h1 after indexing or will this trigger a penalty?
  
  On a Wordpress website which is about 3-4 months old, a customer has created several key service pages without putting all of ;the proper keywords into the title or h1. For example, for an ;English course, he has a title "learn English for life Company name location" without any mention of the word course. The word course does, however, ;appear on the page a few times.
  
  If he adds course into the title and / ;or h1, will this trigger a penalty?
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  Leonie Kramer: Yes you can add or edit title tag and  ;or H1 after Indexing and it will not trigger a penalty as long as you use the( unwritten) SEO rules
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  John Pitcher: +Leonie Kramer ;Many thanks - what are the "unwritten seo rules" to prevent penalty? (Obviously, don't create spammy "English courses town | English lessons town | Learn English town | Business English town". etc)
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  Leonie Kramer: +John Pitcher ; yes that's what i mean: the use of spammy stuff ;-)
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  Michael Tigulo: mostly what I did is, I include the brand name of the site.. example, the title tag is "Family Dentist in Woodland Hills CA | Brand name? is it good?
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  Edwin Jonk: From the expert panel in this weeks SEO Questions hangout on air on 00:42:25 into the YouTube video: https://dumbseoquestions.com/q/can_you_add_keywords_into_the_title_tag_andor_h1_after_indexing_or_will_this_trigger_a_penalty +John Pitcher
  
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  John Pitcher: Many thanks to the panel and to +Edwin Jonk ;