This raises the question, how did you post this question? You wrote it; it is here after all. It exists, and does so by your hand. The obvious answer then, is use the same computer you used to write...
The editor noticed that the word Corigendum was spelt incorrectly, so he inserted a Corrigendum slip in the next print.When he found more than one error, he produced Corrigenda slips.
Either can be correct depending on the context and the tense.I will write you means the same thing asI will write to you.The "to" is understood even if not present, for example:I write to you...
you should write he told you when you are talking in a commandExample: He told you to clean your roomYou should write he said when you are just telling some one somethingExample: He said that 30...