TYPO3 changing an extension with own extension - typo3

Question

I'm trying to create a extension to modify fields in a different extension.
My extension needs to add and disable fields in fe_users over the TSConfig Page.
Ive looked over google how to do this with a own extension. But I didn't find anything usefull that I could work with.
(Edited)
The admin shouldn't be able to see these fields:
Company
Name
Middle name
Address
Zipcode
Land
Phone
Fax
www
Image
TSConfig
Bind a Domain
Redirect after login
Start
Stop
Record Type
These fields should be added
Customer (INT, not able to edit on display) Manditory
swissaxis_id (INT, Unique number) if possible only displayable and
not editing possibility
shop_rights (Textarea, No defined Value. The Rights will be saved
there serialised.)
fe_groups
These fields shouldn't be displayed to any Admin
Bind a domain
TSConfig
Redirect after login
Record Type
I'm thankfull for any Feedback possible.

Answer 1

Here's a link on how you add new fields to fe_users: https://docs.typo3.org/typo3cms/TCAReference/ExtendingTca/Index.html
https://docs.typo3.org/typo3cms/TCAReference/ExtendingTca/Examples/Index.html
I'll give you an example from an old, makeshift extension zusatzfelder of mine that modifies the "pages" table. It's really old, please verify if everything is current. You can also look at any other, "real" extension...
ext_emconf.php (maybe created by extension_builder)
<?php
########################################################################
# Extension Manager/Repository config file for ext "zusatzfelder".
#
# Auto generated 29-08-2011 15:33
#
# Manual updates:
# Only the data in the array - everything else is removed by next
# writing. "version" and "dependencies" must not be touched!
########################################################################
$EM_CONF[$_EXTKEY] = array(
'title' => 'Zusatzfelder',
'description' => '',
'category' => '',
'author' => '',
'author_email' => '',
'shy' => '',
'dependencies' => '',
'conflicts' => '',
'priority' => '',
'module' => '',
'state' => '',
'internal' => '',
'uploadfolder' => 0,
'createDirs' => '',
'modify_tables' => '',
'clearCacheOnLoad' => 0,
'lockType' => '',
'author_company' => '',
'version' => '0.0.0',
'constraints' => array(
'depends' => array(
),
'conflicts' => array(
),
'suggests' => array(
),
),
'_md5_values_when_last_written' => 'a:8:{s:9:"ChangeLog";s:4:"5b94";s:10:"README.txt";s:4:"ee2d";s:12:"ext_icon.gif";s:4:"1bdc";s:14:"ext_tables.php";s:4:"474a";s:14:"ext_tables.sql";s:4:"ead9";s:16:"locallang_db.xml";s:4:"7a92";s:19:"doc/wizard_form.dat";s:4:"0cba";s:20:"doc/wizard_form.html";s:4:"29e8";}',
);
?>
ext_tables.sql
CREATE TABLE pages (
tx_zusatzfelder_contentnav_title_addition tinytext,
tx_zusatzfelder_contentnav_title tinytext,
tx_zusatzfelder_contentnav_disable int(11) DEFAULT '0' NOT NULL,
);
ext_tables.php
<?php
if (!defined('TYPO3_MODE')) {
die ('Access denied.');
}
$tempColumns = array (
'tx_zusatzfelder_contentnav_title' => array (
'exclude' => 0,
'label' => 'LLL:EXT:zusatzfelder/locallang_db.xml:pages.tx_zusatzfelder_contentnav_title',
'config' => array (
'type' => 'input',
'size' => '30',
)
),
'tx_zusatzfelder_contentnav_title_addition' => array (
'exclude' => 0,
'label' => 'LLL:EXT:zusatzfelder/locallang_db.xml:pages.tx_zusatzfelder_contentnav_title_addition',
'config' => array (
'type' => 'input',
'size' => '30',
)
),
'tx_zusatzfelder_contentnav_disable' => array (
'exclude' => 0,
'label' => 'LLL:EXT:zusatzfelder/locallang_db.xml:pages.tx_zusatzfelder_contentnav_disable',
'config' => array (
'type' => 'check',
'default' => '0',
)
),
);
\TYPO3\CMS\Core\Utility\ExtensionManagementUtility::addTCAcolumns('pages',$tempColumns,1);
// http://typo3-blog.net/tutorials/news/addtoalltcatypes.html
// PS: the "after:"... is for placement in the BE, stopped working last week...
\TYPO3\CMS\Core\Utility\ExtensionManagementUtility::addToAllTCAtypes('pages','tx_zusatzfelder_contentnav_title;;;;1-1-1','','after:subtitle');
\TYPO3\CMS\Core\Utility\ExtensionManagementUtility::addToAllTCAtypes('pages','tx_zusatzfelder_contentnav_title_addition;;;;1-1-1','','after:subtitle');
\TYPO3\CMS\Core\Utility\ExtensionManagementUtility::addToAllTCAtypes('pages','tx_zusatzfelder_contentnav_disable;;;;1-1-1','','after:subtitle');
?>
locallang_db.xml
<?xml version="1.0" encoding="utf-8" standalone="yes" ?>
<T3locallang>
<meta type="array">
<type>database</type>
<description>Language labels for database tables/fields belonging to extension 'zusatzfelder'</description>
</meta>
<data type="array">
<languageKey index="default" type="array">
<label index="pages.tx_zusatzfelder_contentnav_title_addition">Untermenu: Vorlauf Titel (zB. "Mehr zur")</label>
<label index="pages.tx_zusatzfelder_contentnav_title">Untermenu: Titellink anderer Text (Standard: Seitentitel; Leerschlag: kein Titel)</label>
<label index="pages.tx_zusatzfelder_contentnav_disable">Untermenu ausblenden</label>
</languageKey>
</data>
</T3locallang>
That's all you need to add new fields – you don't even need the locallang if you just prefer to do 'label' => 'My untranslated Label', in ext_tables.php.